CHAPTER 4

Circuit 3-N

A cipher message from Circuit 3-N, the Nazi clandestine radio link between Argentina and Berlin, solved by Elizebeth’s coast guard unit.

(U.S. National Archives and Records Administration)

William Friedman’s depression returned in December 1941, the month of Pearl Harbor. He had trouble sleeping and was besieged by doubts and morbid thoughts. “Flight, fight, or neurosis,” he wrote on a loose sheet of paper years later during a similar period of depression, trying to describe the feeling. “ ‘Floating anxiety’ which attaches itself to anything and everything. Fear that E. despises me for being such a weakling.” It was scary for a man who prided himself on precision and rationality to feel like he was not in control of his mind or his body. He sometimes referred to this unpleasant condition as the “heebeegeebees,” which he abbreviated as “hbgbs” in private notes to himself.

He did not seek help this time, did not go to a psychiatrist or check himself into a mental hospital—after his experience at the understaffed and punitive mental ward of Walter Reed in January 1941 he was not about to repeat this mistake unless completely desperate—and so, as always, the Friedmans concealed the seriousness of his condition to friends and family, and they continued to work, except for three consecutive days in the spring of 1942 when they stayed home to celebrate their twenty-fifth wedding anniversary. That was the celebration, sleeping in. It was amazing. They were so tired. Elizebeth went to the store and bought a whole chicken and some strawberries and figured she would cook their usual anniversary dinner, a simple feast of roast chicken and strawberry shortcake.

They hadn’t told their friends about the twenty-five-year milestone but somehow the secret leaked, and that evening, to their delight, colleagues and friends knocked on their door, offering silver-anniversary gifts. Fred and Claire Barkley brought a sterling silver round sandwich tray; Jean Chase Ramsay wore a stunning silver dinner gown; Stub and Enid Perkins appeared with an array of flowers in a glass bowl, yellow and blue and white irises, blue delphinium, flame-colored columbine, white gypsophila. To these Elizebeth added pink and yellow roses she thought to pluck from her own rosebushes, and some white and yellow honeysuckle, too, and by the time the next-door neighbor brought two huge armfuls of his own scarlet roses, the house was dizzy with fragrance.

All day long, telegrams of congratulations arrived from friends near and far. Two of the telegrams were jokes written by William, notifying Elizebeth that she had been awarded an honorary A.B. degree from the Sorbonne, “Artiste de Boudoir,” and also a D.S.M. from Harvard, “Doctor of Successful Marriage.” In the second telegram he made light of his mental struggles and acknowledged his wife’s patience and kindness during his periods of illness, though of course he did not use those words:

WHEREAS ELIZEBETH SMITH FRIEDMAN HAS CONDUCTED IMPORTANT SPECIALIZED RESEARCH EXTENDING OVER A PERIOD OF TWENTY FIVE YEARS IN THE VAGARIES AND IDIOSYNCRASIES OF ERRANT HUSBANDS; AND WHEREAS DURING THE CONDUCT OF SUCH RESEARCH SHE HAS BEEN SUBJECTED TO MANY HAZARDS INVOLVING CONSIDERABLE MENTAL ANGUISH, PERSONAL CHAGRIN, DAYS OF ANXIETY, AND NIGHTS OF SLEEPLESSNESS; AND WHEREAS SAID RESEARCH HAS RESULTED IN THE DEVELOPMENT OF ADEQUATE METHODS AND INSTRUMENTALITIES FOR THE CONTROL OF ONE HUSBAND, TO WIT, WILLIAM FREDERICK FRIEDMAN, AND HAS MADE HIM LIVABLE WITH . . .

The children weren’t there to celebrate with their parents. John Ramsay was finishing his sophomore year at prep school in central Pennsylvania, and upon graduation he planned to join the Army Air Corps and head straight to flight school. Barbara was between semesters of college and living in New York City, in an apartment on West Fifty-sixth Street, getting involved in leftist political causes and dating an activist named Hank. “Hank is beautiful,” she wrote to William, “but we’re so utterly different. He lived in the slums and led a gang (because he was the tallest and the biggest) and hated cops and swam in the East River. . . . And now we go to bars and stand at the rail with the workmen and talk about Leninism.”

William had no interest in Leninism but told his daughter she had a good heart. “I hope you will let nothing interfere with your enthusiasm for helping where help is needed, but don’t let the slow, snail’s-pace progress upward and onward get you down,” he wrote. “Remember always that the dawn of man’s conscience is only 3 or 3½ thousand years behind us.”

He had always found this a comforting thought, that the age of barbarism was not long past, that if humans failed to be kind it was because they were still children, historically speaking, and the idea rang true to him as he read and disseminated MAGIC intercepts through the spring of 1942, learning secrets about Japanese war strategy in the Pacific and helping to guide the American response. In June 1942, with the two opposing navies speeding toward a fatal clash at the Battle of Midway, William and his codebreakers moved from the Munitions Building to a new location, Arlington Hall, a former private school for girls located on the outskirts of the city. The army had taken over the hundred-acre campus to provide room for an expanded codebreaking operation. Meanwhile, the navy started transferring intelligence personnel to a similar facility, on Nebraska Avenue, also a former private girls’ school, anchored by a five-story building dubbed the Naval Communications Annex.

These two campuses soon evolved into an American version of Bletchley Park, deeply secret compounds where workers solved puzzles behind barbed wire and never spoke about what they did. Many were women. It’s where the machine era of cryptology began, the era of brute force, women operating machines the size of rooms, American bombes and some of the first IBM punch-card computers.

The women of Arlington Hall and the Naval Annex were mostly WACs and WAVES, members of the army and navy auxiliary programs designed to patch the wartime shortage of male labor. They lived together in barracks and apartments. Hundreds had been trained in secret cryptology courses offered at the Seven Sisters colleges, the likes of Bryn Mawr and Vassar and Mount Holyoke, the professors relying on exercises and concepts first pioneered by William and Elizebeth Friedman. Inside the high-security buildings encircled by barbed wire and guarded by U.S. Marines some of the women sat at long rows of desks, smoking and drinking coffee, and identifying cribs to feed into the bombes, while others operated the bombes that ticked and whirred as they explored the keyspaces of distant Enigma machines. The buildings were hot and unventilated. An Arlington Hall codebreaker named Martha Waller recalled that in the summer, it was often 90 degrees indoors at 8 A.M., and because of the wartime nylon shortage the women couldn’t wear nylon stockings, so “we rejoiced in going bare. . . . Sitting quietly at a desk, one could feel drops of sweat rolling down one’s legs.”

Less than a year from now the navy would force Elizebeth and the Coast Guard Cryptanalytic Unit to move to the Naval Annex, but even then she would never work inside the large, hot rooms with the rows of young women at desks. The unit remained separate, a small elite team doing its own thing. From time to time she and her colleagues would take advantage of the Naval Annex’s technology to make progress on clandestine circuits, relying on IBM punch-card machines to perform statistical analyses that saved time in solving certain ciphers, but the initial assaults on the puzzles emerged from their brains alone. Elizebeth was among the last of the paper-and-pencil heroes. And in the summer of 1942, as the U.S. and Japanese navies clashed in the Pacific and the Nazis ordered French Jews to wear the Star of David, she was taking on the most fiendish challenge of her career, for the biggest stakes.

Exactly as she had feared, the Nazi spies had changed their codes after the March police raids in Brazil. As a direct result of the FBI’s roundup, “Germany was unmistakably informed that the systems had been solved,” wrote the uniformed commander of her unit, Lieutenant Jones, and “the inevitable consequence was that systems on all clandestine circuits were almost immediately thereafter completely changed.” Within two or three weeks the Nazis were back online in multiple locations across South America, and from there the radio network expanded, adding nodes in new cities and countries.

Elizebeth, Lieutenant Jones, and their coast guard teammates watched in frustration as new circuits lit up throughout the summer and fall of 1942—two, then five, then fifteen—each using a different and yet-unbroken code. It was as if the FBI had tried to destroy an approaching asteroid with a single huge bomb but instead just blasted the rock into dozens of sentient fragments able to regenerate and spread wreckage over a wider swath of earth.

The codebreakers were hardly the only Americans troubled by the FBI’s actions in South America. Intelligence chiefs at the army and navy couldn’t believe it either. “Unfortunately, the matter got out of hand, and it became public knowledge that the ciphers used by the espionage agents in that territory were being read by our government,” wrote Joseph Wenger, head of the navy’s OP-20-G, in an internal memo. “It might be much more valuable to the military services to obtain the information flowing through clandestine stations than to close them up.” The British were also taken aback—they had never trusted J. Edgar Hoover in the first place—and as more newspaper stories appeared in Brazil about the court cases of the arrested Nazi spies, local British officials had the stories translated and exchanged secret telegrams about the unfortunateness of it all. “You may care to read the attached rough translation of the story as it appeared in the Brazilian Press,” one diplomat in Brazil wrote to an official at MI5, Britain’s counterintelligence agency. “Rather shattering, I’m afraid.”

The whole fiasco triggered four months of jurisdictional squabbles between the different intelligence services, conducted by memo and conference. The army, navy, and British complained about the FBI; the FBI pushed back. These fights resulted in a series of awkward compromises. The army and navy forced the State Department to promise that no further clandestine stations would be seized without their approval, and all parties recognized that the coast guard had the authority and the expertise to monitor clandestine circuits in the Western Hemisphere. But no one could stop the FBI from doing counterespionage in South America. Hoover had clear authority from the president.

And so, unable to remove his power on paper, the other agencies simply started to freeze him out in secret, routing information so that it flowed around the FBI as much as possible. British relations with the coast guard “grew steadily closer and more informal,” according to the BSC history. “It was understood by both sides that no information received from the coast guard was to be divulged to the FBI.” People literally whispered secrets to one another whenever an FBI representative was in the room; the British observed that “valuable items of intelligence were imparted, hurriedly and sotto voce, either before the meetings began or after they had adjourned.”

In April, the navy ordered the coast guard to stop disseminating clandestine decrypts itself and provide the decrypts to OP-20-G instead, for tighter control. That month, representatives of the army, navy, coast guard, British Security Co-ordination, and Canadian intelligence met at a weeklong conference in Washington to talk shop about radio and spies. It was chaired by Commander Wenger of OP-20-G. The FBI was not invited. Elizebeth was. On the day she explained the coast guard’s approach, April 8, there were seven male naval officers in the room, three male army officers, four male Canadians, five male British, three male coast guard personnel, and her—listed at the top of her cohort in the meeting minutes:

U.S. Coast Guard

Mrs. Friedman

Lt. Comdr. Polio

Lt. Comdr. Peterson

Mr. Bishop

Her Cryptanalytic Unit had grown since Pearl Harbor, but it was still fairly small, with fewer than twenty cryptanalysts, translators, and clerks. They now worked as a team to fix the mess the FBI had caused: to break the new codes on the multiplying circuits and wrangle the chaos into some kind of order.

Until the arrests in March 1942, most spies had been using book ciphers or single transposition systems (a common, Scrabble-type cipher) that were similar in style and relatively easy to break. After March, the spies switched to weirder, harder stuff: running-key systems, double-transposition systems, poly-alphabetic substitution with columnar transposition. They started hopping on the radio at different times of the day in an attempt to avoid interception. They mixed and matched cipher methods in unpredictable ways. One of the new procedures relied on “rail-fencing”—a more sophisticated application of the same principle that Elizebeth and William once used for writing love notes, only now, instead of the plaintext being JE T’ADORE MON MAR or I LOVE YOU VERY MUCH, it was a snippet of German from a Nazi spy in France: HERZLICHE WEIHNACHTSGRÜßE UND WÜNSCHE ZUM NEUE JAHR: “Warm Christmas greetings and wishes for the new year . . . ”

As soon as Elizebeth and Lieutenant Jones could get a handle on one circuit and break the codes, a new one came online. It was a cryptanalyst’s nightmare. Here is a partial list of the circuits the unit was monitoring by the end of 1942:

3-G	Hamburg—Valparaíso (Chile)
3-J	Hamburg—South America
4-C	Lisbon (Portugal)—Lourenco Marques
	(Mozambique)
4-D	Madrid—West Africa
4-F	Hamburg—Lisbon (Portugal)
4-G	Stuttgart—Libya
4-H	Hamburg—Unknown
4-I	Hamburg—Bordeaux (France)
4-L	Hamburg—Gijon (northwest Spain)
4-M	Hamburg—Spain
4-N	Hamburg—Unknown
4-O	Berlin—Madrid
4-P	Hamburg—Madrid
4-Q	Hamburg—Tangier (Morocco)
4-R	Hamburg—Vigo (northwest Spain)
4-S	Berlin—Tetuan (Morocco)
4-T	Berlin—Teheran (Iran)
5-D	Hamburg—The Crimea (USSR)

This was a planet’s worth of radio signals, a one-of-a-kind view of the earth as it convulsed with war, borders blurring, power shifting hands. The Nazis had invaded Crimea, in the Soviet Union. Iran was partially occupied by British and Soviet troops. Morocco was controlled by the Nazi-collaborationist Vichy government of France. Portugal was neutral and fiercely contested by both sides. Libya had been conquered, for the time being, by Italian and German troops. The Nazis had spies and saboteurs in all these places, sending back information over clandestine radio transmitters, and Nazi diplomats and even military officers sometimes borrowed the transmitters to speak with Hamburg and Berlin in times of transition and stress. The clandestine network, though built for espionage, was really just another communications channel, a way for Nazis of all sorts to share information in a fluid situation. Nikola Tesla predicted in 1926 that “when wireless is perfectly applied the whole earth will be converted into a huge brain.” The clandestine network was the Nazi brain, fragmentary but already encircling the earth, and adding new synapses at a fearsome clip.

The information flickering through the brain wasn’t necessarily accurate—some circuits seemed to contain little but “a miscellany of military information partly factual and partly distorted,” wrote Lieutenant Jones in a 1944 memo, “evidently pieced together from barroom conversations with merchant seamen”—but even the garbage circuits were useful to monitor. “In all cases,” Jones went on, “the reading of these circuits provided assurance that if any serious leak of vital information did occur we would learn of it almost before it became known in Germany and would be in a position to provide immediate safeguards.” In other words, the Nazi brain served as a kind of early-warning system for the Allies. Beyond that, the solved messages provided a wealth of information about the Nazi grasp of American military capabilities, because when Germany asked the spies for information about U.S. ballistics or antiaircraft guns, they were revealing that this was information they lacked.

Elizebeth raced to stay on top of the shifting codes, the proliferating patterns. Her worksheets grew weird, beautiful. She filled the grid squares with letters and numbers that made different geometric shapes when you stepped back and looked at the worksheet from a distance. Some of the shapes were parallelograms, some looked like stairs, others like labyrinths. She pulled mischievous letters from the sky and sorted them on the page. The invisible world was all out of whack, misaligned, and she had this set of tricks to knock it back into order.

Once Elizebeth broke the code on a circuit, she solved every message that she came across, no matter how trivial or personal. Sinister messages, personal messages, sober messages that spoke of bombs and guns and ships and submarines, messages that just seemed bizarre. (Berlin to South America: “Can you procure details about the process of making explosives from cacao?” Cacao is the main ingredient of chocolate.) She learned intimate details of the spies’ lives. Berlin informed a spy in Iceland that his wife, Erika, had given birth to a healthy baby girl, Jutta. Several times a family member of a spy was allowed to transmit a personal message from Berlin. One of the wives shared Elizebeth’s first name, although she spelled it in the traditional way. “My dear JOHNY: My heartiest congratulations on your birthday and thousands of loving greetings and kisses from your Elizabeth.”

Elizebeth Friedman solved and disseminated these messages like all the others. Such were her weapons against fascism: pencils, puzzles, circuits, names, dates, places, check marks, handwritten notes affixed to typed pages with staplers, stacks of solved messages rising with the hours and days and weeks.

And she stepped lightly as she worked. Her name did not appear on the documents of the Cryptanalytic Unit. She wasn’t the top commander anymore, so she didn’t write official memos to other parts of the intelligence community (Lieutenant Jones did that), and she didn’t meet directly with FBI officials (Jones did that, too). Jones’s name was the name typed on memos about clandestine radio traffic that circulated within the navy’s OP-20-G. And although Elizebeth was not shy behind closed doors, sometimes quarreling with Jones about the direction of their work, disagreeing about which puzzles were more urgent or less urgent to tackle (she found his judgment clouded sometimes by careerism, a hunger for promotion that was irritating), she didn’t mind being anonymous on the page. Her experiences as a cryptologic celebrity in the 1930s had convinced her that in this secret world, attention was a kind of poison. She said after the war that she considered herself “one of the workers” in the Cryptanalytic Unit—she was certainly being paid like a worker, not a leader, earning $4,200 a year, equal to $63,000 today, as a P-5 civil servant, a middle classification of government employee—and this combination of Elizebeth’s tendency to minimize her own contributions and Jones’s role as commander is one reason that her role in the war would go undiscovered for so many years.

Still, unavoidably, she left fingerprints in the records, little traces of her labor. Her initials, ESF, were typed at the bottom of some coast guard decrypts. Her handwriting appeared on many notes stapled to the decrypts, preceded by a code name, “GI-A,” that meant “analyst” and was shared by others in the unit, and sometimes she wrote directly on the decrypts themselves, a characteristic burst of red or blue colored pencil next to a particularly crucial name or phrase, scribbled in the distinctive slant of Elizebeth’s hand that had not changed since she was a college student writing in her diary.

At the end of the day, the unit was hers, not Jones’s. She was the one who first proposed its creation in 1930. She staffed it. She trained the cryptanalysts. She guided its work over the years, building it into a powerhouse. This gave her an informal authority. People who had been paying attention knew that she was the beating heart of coast guard codebreaking. In December 1942, two British intelligence liasons met with Elizebeth in Washington to talk about closer coordination between Bletchley Park and the Coast Guard Cryptanalytic Unit. One of the liasons, Major G. G. Stevens, described the meeting in a “Most Secret” cable to his superiors in Britain and suggested that they arrange for a coast guard representative to visit Bletchley. “For this one would like to see Mrs. Friedman go,” the British official wrote, “but probably at this end”—i.e., the Washington end—“it would be considered more suitable to send Lieutenant-Commander Jones, the official head of the section.”

Given the tension of her job, the pressures of extreme secrecy, and the bleary afternoons stacking alphabets, Elizebeth was glad for her friendship with F. J. M. “Chubby” Stratton, the British astronomer and radio expert who looked like Santa Claus. He was a calming presence. He had a habit of appearing at Elizebeth’s desk at unexpected times. She would be at her desk, nose buried in some problem, and look up to see him there, smiling. Without ever revealing anything about himself, he had a way of making you feel like you had known him forever, and that everything would be OK. And, of course, he was brilliant—a bit of a tinkerer. He loved the challenge of locating hidden radio stations. He had invented a device he called a “snifter,” a little piece of electronics that fit in the pocket and allowed a person on foot to covertly pinpoint the exact location of a pirate radio transmitter within a building, accurate to the floor. He managed a staff of direction-finding experts who cooperated with the FCC to narrow down the location of pirate signals.

Through terrific effort, teamwork, and long hours, the coast guard codebreakers and their partners finally regained mastery over the clandestine circuits after an unpleasant period of blindness. By winter 1942, Elizebeth’s eyes had adjusted. In the dark, lights out, she was watching them now, one letter of the alphabet at a time. She had the Nazi brain in a jar on her desk, alive and glistening, electrodes running out to her pencil. The unit had conquered every new circuit, every new code that came online that year.

Except one.

The circuit exchanged its first messages on October 10, 1942. The messages seemed to resist solution. She wondered if it might be an Enigma circuit, the messages encrypted by an Enigma machine of some kind.

She called it Circuit 3-N.

Presumably the messages on Circuit 3-N were sensitive enough to require a stronger-than-usual code, so she guessed that the messages must be important. She was more correct than she knew: in the end, the fate of the Invisible War would turn on the sinister frequencies of Circuit 3-N.

For now the anxiety of an unsolved puzzle was more than enough to motivate her. Here were some messages she couldn’t read and she wanted to read them. The code simply had to be smashed.

At weekly radio intelligence meetings with her British and FCC colleagues, she talked about Circuit 3-N, and all the agencies chipped in with clues. The FCC determined that one of the stations was located in Europe and the other in South America, and the British confirmed the FCC’s bearings.

New intercepts from Circuit 3-N arrived in Elizebeth’s office each week. By December 1942 she had accumulated twenty-eight encrypted messages. A cursory analysis showed telltale signatures of an Enigma machine.

Elizebeth and the coast guard had already solved one Enigma, back in 1940, a commercial Enigma whose wiring scheme was already known. Now they were up against an Enigma that would turn out to be a machine of unknown wiring, never before solved. It was the real thing in the wild. She had to find a way in.

The Argentine sun felt good on his face and warmed his scalp through his thin layer of brown hair. Gustav Utzinger liked living in Buenos Aires. It was a beautiful old city—clean, musical, full of friendly people who did not ask too many questions. At a small shop in the heart of the city, 1511 Calle Donado, not far from the water, he built and repaired radios for legitimate paying clients.

He was twenty-eight. It did not seem crazy to imagine that he might survive the war, get married, and have children, either here or back in Germany. He had people in Berlin who adored him and worried about him. Utzinger’s girlfriend worked at AMT VI, which gave her access to the radio transmitter, and she often sent him personal messages from her and from Utzinger’s loved ones. She signed the messages “Blue Eye” and called him “Dark Eye.” Sometimes “Blue Eye” transmitted a message written by Utzinger’s grandmother in Berlin, who called herself “the Ahnfrau.” He tried to take care of his grandmother from afar, sending packages of food from South America, tinned meat and coffee. She told him in radio messages that the packages were greatly appreciated and boosted her spirits. “I am sitting with . . . BLUE EYE and with a bottle of wine, celebrating your birthday,” she wrote once. “On the one hand, I should like to have you here, on the other hand, I am proud of your accomplishments . . . received 2 packages this year. Was very pleased and thankful . . . I am well. Most cordial greetings. THE AHNFRAU.” She asked him to remember to brush his teeth.

If it had been up to Gustav Utzinger, he may have spent the rest of the war running his little radio business there in Buenos Aires, making good money, placing advertisements in newspapers, doing everything on the up-and-up. But he was in the SS, the elite vanguard of the Nazi state, and the SS did not care about his personal dreams and ambitions, which is why, in the shop’s basement, during the final months of 1942, he resumed his “natural patriotic efforts for my Fatherland,” and made himself busy assembling and testing a new generation of clandestine radio sets, at the urgent request of his Nazi superiors.

It had been eight months since the FBI tried and failed to smash the Nazi network in Brazil. After the arrests, Utzinger had floated around for a while, trying to earn money to support himself. Escaping to Asunción, Paraguay, he got a job as a radio technician for the Paraguayan air force, which was commanded by an energetic fascist named Pablo Stagni. Under Stagni’s wing, Utzinger built transmitters for the military and taught Paraguayan officers the fine points of radio. Sometimes he would see a few of his former Nazi colleagues kicking around Asunción, but all they did was talk—except for one day when they burned the reels of Charlie Chaplin’s The Great Dictator in the public square.

It wasn’t until Utzinger traveled to Buenos Aires that he got pulled back into the clandestine radio game.

He went there with Stagni, who was trying to convince the Nazi naval attaché, Dietrich Niebuhr, to sell him a gun sight for some ancient Krupp cannon that the Paraguayans had seized from the Bolivians during a previous war. Dietrich Niebuhr was far more interested in Utzinger than the cannon and started to bend the radio wizard’s ear. Niebuhr said he was under extreme pressure from Berlin to build a clandestine radio transmitter here, and he needed Utzinger’s help.

At this point in the war, Argentina was a far more amenable climate for clandestine radio than Brazil. The Brazilians had leaned toward the Allies as the war developed; Argentinians headed in the opposite direction. An American Jewish novelist named Waldo Frank toured Argentina in the summer of 1942 and noticed “a spawn of little nazi and nationalist papers,” he wrote in an account of his journey. Frank traveled through cities and small towns delivering speeches about the value of democracy, and in every town a pro-Nazi newspaper attacked. He sensed that Argentina’s conservative government, controlled by corrupt landowners, had “a very uncertain grip upon the country” and that fascists had infiltrated the police. By the end of Frank’s tour, the government had declared him persona non grata, and before he could escape, five cops stormed into his hotel and beat him on the skull with truncheons.

Naturally the Nazis wanted to take advantage of this receptive atmosphere, especially since they were losing friends around the world at a rapid rate. Only two nations in the Western Hemisphere now maintained formal relations with the Reich—Chile and Argentina—and in early 1943, Chile would sever the link, making Argentina the lone holdout. This is why Berlin and Dietrich Niebuhr were desperate for a wireless link. Argentina was one of Germany’s only listening posts in the hemisphere, one of the last places where it was still possible to obtain reliable intelligence about anything happening in the West, including the United States. They had to keep a line open at all costs.

Niebuhr gave Utzinger a powerful Seimens transmitter he had been keeping at the embassy, and in the fall of 1942, Utzinger took it to a small farm outside the city and began making tests. But as it turned out, Niebuhr wasn’t the only Nazi in Argentina who needed radio assistance. Utzinger was also approached by an Abwehr spy named Hans Harnisch, code name “Boss,” an employee of a German steel firm in Buenos Aires. He also wanted a wireless link to Berlin.

Then, in January 1943, the most mysterious spy of all suddenly appeared in Buenos Aires: Hauptsturmführer Siegfried Becker, a.k.a. “Sargo.” He had stowed away on a Spanish ship, paying off the crew to smuggle him through customs.

And in his luggage, all the way from Germany, he had brought an Enigma cipher machine.

Becker looked the same as always—blond hair, nice clothes, a dirty mustache, bizarrely long fingernails—but Utzinger thought he detected a new gleam in Becker’s eye. He was vibrating with ambition. Becker said that in the months ahead he would need Utzinger to transmit very sensitive information to Berlin. The “embassy crowd” must not be able to read the messages. Whatever Becker had in store for his next chapter, he intended to keep it close.

Utzinger now found himself in a nearly impossible position. Three men from three rival agencies had asked him for radio assistance: Niebuhr with the German embassy, Harnisch with the Abwehr, and Becker with the SS. In theory, he could create three separate radio stations, but this wasn’t practical given the limitations of his own equipment. One powerful station was preferable to three weak ones. Instead of building three stations, then, Utzinger decided to trick Berlin into thinking that he had. He designed a mythical radio organization that only existed on paper, a “Potemkin network,” so that each agency in Germany would feel it controlled its own station in Argentina. He called this network “Bolivar” and told Berlin that it consisted of three sections, Rot, Gruen, and Blau—Red, Green, and Blue.

Red was Becker, Utzinger, and their SS collaborators.

Green was Hans Harnisch and the Abwehr.

Blue was the “embassy crowd.”

The ruse gave Utzinger the freedom to run his operation as he saw fit without needing to explain his every technical choice to Berlin. He was determined to avoid the mistakes that had gotten the men arrested in Brazil, and with Becker’s help he got to work. Together they recruited a new team of spies from Buenos Aires and surrounding towns, “42 loyal and seasoned collaborators,” including German immigrants and working-class Argentines who believed in fascism. Utzinger selected new radiomen and drilled them in good security practices. Limit transmissions to short bursts; send decoy messages full of garbage text on prearranged frequencies; transmit at different times each week; never repeat the same message twice.

“I am teaching my boys tough wireless discipline,” he radioed to Berlin. “The Yankees are copying every dot of our transmission.”

In addition to the new radio link, the spies carved out another useful channel to Berlin, building a courier system that relied on Spanish sailors to smuggle packages and luggage on Spanish vessels. These men, paid in pesos and known as “wolves,” allowed Becker and Utzinger to receive shipments of money, pharmaceuticals to sell for cash, and radio parts—items necessary to keep the network afloat. And through the wolf system and other sources, Utzinger also obtained crypto machines. He now had two Enigmas at his disposal, plus a pocket watch–size Kryha device called a Liliput, small and light and easily concealed.

By the end of February 1943, Utzinger and Becker had everything in place: a new radio system; crypto machines, including Enigmas, the best available, each message a perfect tiny fortress; a team of collaborators. They were ready to transmit reports to Germany in volume. On February 28, Becker hopped on the radio and sent Berlin a cheerful progress update:

New organization established with LUNA. LUNA has assembled in splendid fashion a circle of co-workers. Spread and prepared so that I am able to start immediately with work according to plan. SARGENTO.

Berlin replied with glee. “Old boy, now we are off,” they radioed. “Test message. Cordial greetings to all. We are awaiting your blind traffic there on Monday, Wednesday and Saturday at 0200 and 0400.”

The spies’ SS leaders back home, the officers of AMT VI, could not have been happier to hear that a door was opening in Argentina. The winter months of late 1942 and 1943 had been grim ones in Germany. The Red Army was crushing the Wehrmacht in Stalingrad, and although Nazi censors blocked reports of losses, rumors leaked. In the snow-dusted cities of Germany, it was difficult to find toothbrushes, belts, bicycle tires, and toilet paper. Restaurants complained of patrons stealing glasses. On February 18, at a rally of twenty thousand in Berlin, Minister of Propaganda Joseph Goebbels finally admitted that the Battle of Stalingrad was lost and called for “a war more total and radical than anything that we can even imagine today,” an apocalyptic death struggle against the Allies and against Jewry.

All in the homeland that season was darkness, danger, frost—and yet in Argentina, Becker and Utzinger reported, it was the height of summer, and they were making interesting friends.

Becker, for instance, was cultivating a relationship with Juan Domingo Perón, the future three-time president of Argentina, now just a young army colonel with a taste for moral larceny. (He lived with a fourteen-year-old girlfriend whom he called “The Piranha.”) Perón belonged to a secret lodge of military officers, the United Officers’ Group (GOU), that aimed to overthrow the Argentine president, and he was already thinking beyond his own nation. Inspired by Hitler’s domination of Europe, Perón imagined himself at the head of a nationalist movement sweeping across all of South America.

His ambition exceeded his reach. He didn’t yet have the contacts that a wider revolution would require. But Siegfried Becker did. During his decade with the SS, working in Germany, Brazil, and Argentina, Becker had gotten to know all kinds of influential South Americans: among them lieutenants, generals, diplomats, and police captains. He carried a small notebook with their phone numbers. These contacts—Becker’s little black book of nationalists and fascists—made him an alluring figure to Perón and his friends, and soon the Argentines hashed out an informal deal with the Nazi spies.

Each side would get something it wanted. The Argentines would share secrets about the United States and protect the spies from the FBI and other Allied law agencies. In exchange, the spies would operate behind the scenes to extend Argentina’s influence across South America, connecting revolutionaries in one country to like-minded men in another. They would plot coups, overthrow governments, and install fascist-friendly regimes.

The ultimate goal was to assemble a bloc of nations aligned against the United States. “Hitler’s struggle in war and in peace will be our guide,” Perón and his GOU plotters wrote in a covert manifesto. “With Argentina, Paraguay, Bolivia, and Chile, it will be easy to pressure Uruguay. Then the five united nations will easily draw in Brazil because of its type of government and its large nucleus of Germans.”

With Brazil fallen, the “continent will be ours.”

At her coast guard desk, Elizebeth reached for a fresh sheet of grid paper. Circuit 3-N. Argentina to Berlin. The unknown Enigma machine.

Twenty-eight unsolved messages from Circuit 3-N now sat in a pile on her desk. She wrote the twenty-eight ciphertexts on the worksheet in pencil, one on top of another, assembling a stack of text so she could solve the messages in depth, like she had done in 1940 to solve the commercial Enigma machine.

The twenty-eight messages all appeared to use the same key—a huge gift to the codebreakers from their Nazi adversaries. It made things easier and allowed Elizebeth to begin solving the individual messages.

She made a frequency count of the letters in the columns. The cipher letter H appeared seven times in column no. 2, four times in column no. 3, and so on. This was enough to start guessing at the plaintext letters. Each column was its own MASC, a mono-alphabetic cipher, and she hopped around, penciling plain letters in the columns and guessing at German words across the rows, like bericht (report) and wir hoeren (we hear).

She was following the path she had blazed in 1940 with the commercial Enigma, using her experience with that old machine to discover “an entering wedge” with this new one, and then hammering the wedge until the damn thing split. The team was still relying on the geometry of patterns. Step one: Line up the messages one on top of another. Step two: Solve the plaintexts in depth. Step three: Use the resulting alphabets to deduce the wheel wiring. Step four: Exploit the wiring knowledge to reveal the new keys whenever the adversary changes them.

This time, the coast guard had some competition. Across the sea, at Bletchley Park, the secret British codebreaking campus, a unit called Intelligence Service Knox (ISK) was attacking the same Enigma, trying to solve it independently of the coast guard. Bletchley had been breaking spy ciphers since the start of the war. Now the two Allied teams each solved this new Enigma at about the same time, in December 1942, by different methods that ultimately got them to the same place.

The machine turned out to be a G-model Enigma designed for the Abwehr, similar to the commercial Enigma but with wheels that stepped less regularly. Within the high-security universe of Enigmas, it was a medium-security model, more puzzling than the commercial machine but less so than other Enigmas. Decades later, Elizebeth called the G-model a “less superior Enigma that was used by Germany and her confidential agents—her spies.” At the moment, however, solving the machine felt like victory. “There was much celebration,” an NSA historian reported after the war, in an interview with Elizebeth.

Now the coast guard could read the messages backward and forward—the old messages already intercepted and the new ones incoming. Looking at the plaintexts, the codebreakers confirmed that the South American end of the circuit was in Buenos Aires, Argentina.

Also, the names of three colors popped out in the messages: Green, Red, and Blue. The spies were tagging their notes by these color names, and each color seemed to represent a different spy leader using a different code.

It was as if multiple groups of Nazi agents had converged around Buenos Aires and were sharing this one circuit, pooling resources to make a kind of last stand.

Having broken into the Green messages, the coast guard codebreakers turned their gaze to the Red traffic, which they already knew was encrypted with a device that the Germans called Lily. “Following messages all enciphered with LILY,” Berlin had radioed in February 1943. It seemed clear to Elizebeth and her coworkers that Lily was short for Liliput, as in a Kryha Liliput, a miniature version of the German cipher device.

The Liliput was somewhat more complex than earlier Kryha models, but as a rule, Kryhas were less secure than Enigmas. Elizebeth walked to her shelf, picked up a Kryha, and examined it with her colleagues. It was an older model, but the principle was the same. Two concentric alphabet wheels stepped against each other, the stepping regulated by a control wheel set to a certain starting position. After a month of work, the codebreakers recovered the key with the help of punch cards, the IBM crunching and tabulating the frequencies of certain juxtapositions of cipher letters that helped them understand how the letters were distributed and offered clues about possible keys that were then tested to see if they produced sensible plaintext.

Now the coast guard was able to read the bulk of the circuit’s traffic, the Red messages as well as the Green. (They would never solve the Blue messages, but it didn’t matter.)

And what two names popped out in the plaintexts?

“Sargo” and “Luna,” Elizebeth’s old friends.

She recognized the aliases of the spy and the radio wizard. She had first encountered them on the Brazil circuits in 1942, and now, apparently, the duo had reunited in Argentina.

This alone meant that Circuit 3-N was important—the presence of these two important individuals, “Sargo” and “Luna.” But there was something else that concerned her. The men seemed to be building a completely new wireless organization, bigger than before. They were hiring radio operators and obsessively testing new radio equipment.

“We have antenna 100 meters long beamed on Berlin,” the spies tapped out to Berlin one day. “Hope you like it.”

It was clear to Elizebeth that the Nazi network in the West had shifted to Argentina, and that the men were preparing the ground for a significant espionage effort. Something big was about to happen.

Unfortunately for Elizebeth, right as she was starting to figure this out, the navy forced her to interrupt her work and pack up her office.

In March 1943, the coast guard codebreakers were ordered to move from their longtime home at the Treasury to the former girls’ school now known as the Naval Communications Annex, the temporary wartime facility on Nebraska Avenue. Elizebeth had to pause her assault on Circuit 3-N while she got settled in the new location. She claimed an office on the second floor and spoke little to anyone outside of her own team. A coast guard employee who worked two doors down from her in the Annex later recalled, “Our work was compartmented. We went as a group for lunch, but the conversation was never about work, but concerned current events—the way the war was going, etc.” Elizebeth worked a little with a few of the SPARS, members of the coast guard women’s auxiliary, and she sometimes interacted with the young WAVES and WACs on a purely social basis, outside of the Naval Annex, inviting them to her home for tea and asking how they were getting along in Washington. One evening, Martha Waller, the codebreaker at Arlington Hall, returned home to her D.C. apartment to find Elizebeth and William Friedman sitting at dinner with five of her roommates. One of the roommates’ father apparently knew William and had set up the dinner. Waller was dumbstruck. The Friedmans, she had heard, were legends. “I think I was mesmerized, and I know I said next to nothing,” Waller recalls. Here is what she remembers about Elizebeth: “She looked, sounded, and behaved like the professor of English she might well have become.”

The month after Elizebeth relocated to the Naval Annex, her husband left the country on his first big mission since his mental breakdown two years earlier. William Friedman traveled to Bletchley Park at the request of the army, which wanted him to negotiate an agreement to share information, expertise, and blueprints for building bombes. He succeeded, but his depression came back while he was overseas, manifesting as insomnia. He swallowed pink Amytal pills to knock himself out and in a personal diary of the trip he repeatedly mentioned sleep problems:

TUESDAY APRIL 27 . . . Bed at 10:30 but too tired for good sleeping.

SUNDAY MAY 2 . . . Poor sleeping for some reason or other, maybe tetanus shot still working.

MONDAY, MAY 24TH . . . Got up at about 1 a.m. and took two small pills from Washington cache but didn’t do much good. Awoke early & not at all refreshed. Guess this work is very exhausting mentally & I hope to get through with it soon.

MONDAY, MAY 24TH . . . I’ve noticed that on days when I am “tense” & have “heebeegeebees” I sleep well in night but when don’t have them, sleep not so good. —Haven’t had hbgbs for many days now. Wish I could solve this mystery of myself.

Elizebeth didn’t see these diary entries but imagined that William must be under great stress, and she worried about his mental state. Throughout April and May, she wrote him constantly while he was gone, sending at least fourteen letters to the military attaché at the American embassy in London for delivery to his secret location. In the letters she focused on small details of life in Washington: their lawn that was cracked and dried from the spring sun; a party with some family friends where they all drank too many old-fashioneds and stayed up until 2 A.M. singing songs around the piano. “I will create pictures for you of the scenes and people present and so seem like a momentary return for you.” She mentioned a mutual friend, Colonel John McGrail of the signal corps, one of the intelligence professionals who had written critical annotations in William’s copy of The American Black Chamber. Like William, McGrail was brilliant, prone to depression, and kind; he sent Elizebeth a corsage of violets on Easter, “the dear sweet thing,” Elizebeth wrote to William, adding that McGrail “seemed more depressed than ever.” She said that William’s Telechron machine in the library, an electric clock, seemed to be ticking at faster-than-normal speed: “Even your telechron misses you. It is running crazily.”

She mentioned that she had been skipping breakfast to stay slim and was smoking cigarettes in the evenings, a rare admission that she herself was stressed and overwhelmed by the mental strain of her job. One summer day, the temperature inside the Naval Annex reached 110 degrees, with no air conditioning. She was dripping sweat onto her worksheets. Everyone was. The navy commanders declined to send people home, saying that a war was on.

There was a real danger that if Elizebeth relaxed, even for a week, her Cryptanalytic Unit might fall behind and never catch up. Throughout the summer of 1943, the Nazis rolled out extensive reforms of their crypto systems to improve security. The orders were issued by a respected Nazi cryptographer, Fritz Menzer, who led a staff of twenty-five cipher experts in the High Command of the Wehrmacht. Spies who were still relying on hand ciphers discarded their old methods for Oberinspektor Menzer’s new procedures, and the coast guard codebreakers had to adapt. They worked furiously to solve “Procedure 62,” a double transposition system based on a thirty-one-letter key phrase. In this one, the letters of the message were scrambled once and then scrambled again, and only unscrambled by means of a key phrase that was itself scrambled based on the number of the month.

Clandestine circuits in Spanish-speaking countries began to use Procedure 62. Another new crypto system, “Procedure 40,” adopted by spies in Madrid and elsewhere, was a substitution method combined with double transposition, both steps sharing the same key phrase. In the substitution step, the phrase was written in a 5-by-5 square of letters. One such key phrase that Elizebeth’s team unearthed was the Spanish proverb donde menos se piensa salta la liebra. Written in the 5-by-5 square, skipping all repeated letters, it looked like this:

D	O	N	E	M
S	P	I	A	L
T	B	R	C	F
G	H	K	Q	U
V	W	X	Y	Z

Literally the proverb means “Where least expected, the hare jumps,” though a better translation might be “Opportunity knocks where it is least expected.”

And whatever else demanded her attention during the day, Elizebeth kept going back to Circuit 3-N, the link between Argentina and Berlin.

She was more convinced than ever that Circuit 3-N was the most important circuit of all. The volume of traffic abruptly rose in April and continued to expand every week. Some days they sent as many as fifteen different messages to Berlin and just as many replies traveled in the opposite direction—an explosion of new leads for Elizebeth and her team to chase down, a deepening abyss of Nazi text.

Germany seemed as hungry as ever for information about the United States, asking questions about U.S. weapons capabilities and political figures. (“Are there differences of opinion between Roosevelt and his Jewish advisers, above all Roseman, Morgenthau and Frankfurter?”) Berlin often sent requests to the spies in long numbered lists:

1. The Fisher Co. in Detroit reportedly constructed a new anti-aircraft gun of about 12-centimeter caliber, which is fired by remote control. Urgent question: Construction, mode of action, performances.

2. What is manufactured in [Henry] Ford’s shop in Iron Mountain? Size of the plant? Since when? Monthly production?

3. The USA armor bombs: What caliber? Kind of the material? Cross section plan, explosive charge, quantity of (5 letters garbled) and detonator. Is “Explosive D” used?

4. Details on new development and production of armor-piercing arms and in this, air bombs of USA and England in particular.

5. Details and particular on development and introduction of rocket weapons . . .

Such messages were concerning, of course, but they were also straightforward and familiar. Elizebeth had seen hundreds like them on other circuits. What was completely new and sinister about Circuit 3-N was the political intrigue shining through the plaintexts—a whole other level of conspiracy and malice. “Sargo” and “Luna” weren’t just two guys transmitting the shipping news anymore. They had friends across the continent, poised to act in the name of revolution. They were building a secret army.

For one, it was clear to Elizebeth that the spies had forged an intimate working relationship with powerful Argentine figures. On June 4, 1943, a group of generals had occupied the presidente’s mansion in Buenos Aires, the Casa Rosada, deposing the old regime and installing a new presidente, Pedro Pablo Ramírez. The messages contained references to Ramírez (the Nazis called him “Godes”) and other coup figures, including Juan Perón and Captain Eduardo Aumann, code name “Moreno,” now a high official in the Argentine foreign ministry. Elizebeth noticed that a Nazi agent named “Boss” (Abwehr leader Hans Harnisch) was regularly meeting in secret with these men. “Another important conference with [Presidente] GODES revealed his willingness for energetic collaboration in the interests of the Axis powers,” “Boss” radioed to Berlin on July 24, 1943, adding later that Aumann and others were “ready in every respect to promote mutual interests,” and that “the USA is considered greatest enemy.”

It wasn’t shocking for Elizebeth to learn that Argentina, a supposedly neutral country, was cooperating with Germany behind closed doors. But the scope of the cooperation was surprisingly extensive. She was seeing glimmers of incredible clandestine missions. “Boss” wrote in one message, “Through our efforts Argentine Government has established close contact with nationalist groups in Chile, Bolivia and Paraguay; even with Brazil through V-men residing here.” Argentina alone was not enough for the Nazis: They were conspiring to overthrow the governments of Bolivia, Chile, Paraguay, and Brazil. They were trying to run the table, to turn the continent fascist.

“Sargo” appeared to be the man behind the scenes, the invisible agent traveling from country to country, meeting with revolutionaries, bringing money and information, linking them to one another. He told Berlin he had secured the cooperation of the Paraguayan air force chief, Stagni, who “is completely in our camp” and was glad to fly him around the continent on Paraguayan planes. “Sargo” said he was optimistic about the prospects for a military coup in Bolivia, where he had formed a cell of conspirators with the Bolivian minister of mines and an attaché named Elias Belmonte. And as “Sargo” schemed and plotted in the dark, working on the gritty details of revolution, his colleague “Boss” continued to meet with the Argentines and talk about the big picture. In late August “Boss” attended “a secret session of high officers and officials” of the Argentine government and radioed the following to Berlin:

Final objective is said to be formation of a bloc of South American countries, which would itself protect its interests, without tutelage of others who pretend to do this. Bolivia must not only be freed from USA influence, but also establish social justice. Argentine can carry out this together with or even in spite of the Bolivian government. Great progress was achieved in negotiations with Chile and further improvement is to be expected. The days of the Rios government with its ambiguous leftist policy are numbered. Chilean military circles had prepared everything in order to follow Argentina’s example [i.e., to launch a coup] . . . haste is necessary . . . there is dissatisfaction with [Paraguayan president] Moringo. It was intimated that change in government there is not excluded . . .

Perhaps boldest of all, the spies seemed to be arranging a secret weapons deal between Argentina and Nazi Germany. They were trying to figure out a way to get guns and bombs from Berlin to Buenos Aires without the Allies knowing.

Elizebeth was able to follow every twist of the weapons deal in the plaintexts. The details, she discovered, would be negotiated in Berlin by an Argentine envoy, a local man who would sail from Buenos Aires under diplomatic cover. He had been promised meetings with Himmler and Hitler. “An agent will depart from Argentina to Germany,” one of the spies informed Berlin in July. “Name, rank, mission to follow.”

In a subsequent message, Elizebeth learned the man’s name: Osmar Hellmuth.

Donde menos se piensa salta la liebra. She heard a knock.

Osmar Hellmuth had never felt so important before. He had never done anything quite this exciting. One minute you are at the German Club of Buenos Aires, having a nice conversation with some nice German fellows in riding boots, and the next minute you are back at your flat on the Calle Esmerelda with some different German fellows, discussing an international weapons deal, and you are introduced to a man with unusually long and curling fingernails and told that “this gentleman” will make all arrangements for you to sail across the world for a private audience with the Führer.

Hellmuth—forty, not too bright, heavyset, with a red mustache and red hair combed straight back—was “easy prey” for the Nazi spy ring, British officials would later conclude. A low-ranking naval officer, he handled minor diplomatic duties for the Argentine government. His portfolio was not enough to make him powerful. But it was enough to afford the kinds of diplomatic protections that brought him to the notice of Siegfried Becker.

It was the summer of 1943, and Becker’s ambition was growing with his power. He now lived in an upscale neighborhood of Buenos Aires, not far from the palatial home of Juan Perón, whose star had been rising after the coup.

The two men spoke often, in secret, which is how Becker came to understand that the Argentines had a pressing desire for weapons. Fearing an invasion from Brazil, their enemy and main rival on the continent, they wanted Becker to help procure weapons from Berlin. This was a complicated request. At this stage of the war, weapons were hard to come by—Germany could not easily spare them—and Becker could not simply ask Berlin for weapons because the foreign ministry was controlled by a bureaucratic rival of SS foreign intelligence. The only way to get the weapons, then, was in secret, without “the embassy crowd” finding out.

This is when Becker approached Osmar Hellmuth, the former insurance salesman, and made him an offer.

Becker explained to the naive Argentine that the sale of weapons had to be negotiated in person. An envoy was needed, an intermediary. If Hellmuth agreed to accept the mission, Becker explained, he would board a ship in Buenos Aires, the Cabo de Hornos. The ship would sail to the port of Trinidad on the northern shore of the continent, where British officials searched all vessels bound for Europe, and then depart for Spain. Upon Hellmuth’s arrival in Bilbao, Spain, he should check into the Hotel Carlton and wait for an SS agent to approach and speak the words “Greetings from Siegfried Becker.” Hellmuth was to reply, “Ah! The Hauptstürmfuhrer!” The SS man in Bilbao would then arrange for Hellmuth to meet with Nazi leaders, including Himmler and Hitler, and after the deal was arranged, Hellmuth would be rewarded with a cushy consular job in Barcelona.

“I had a marvellous opportunity to go to Europe,” Hellmuth explained later, “free of expense with a good salary, on an extremely interesting mission, and with good prospects.” He didn’t understand the risks. Becker did. Becker just assumed that if the mission failed, or if the Allies found out about it, no one would be able to trace its genesis back to him. In a brilliant espionage career, this may have been his one fatal mistake.

Becker wasn’t alone in his miscalculations that summer. Gustav Utzinger, the ring’s radio expert, was also failing to grasp the danger of his position. The Americans—Elizebeth Friedman and her team—had broken his cipher machines and were now reading his every transmission, but for Utzinger, the prospect of a Yankee breaking an Enigma machine was beyond his comprehension.

This wasn’t to say that he slept soundly at night; like any good radio expert, Utzinger lived in a fog of professional paranoia. He simply assumed that any breaches of his network must be the fault of his incompetent counterparts in Berlin, a consequence of their “dilettantism and lack of imagination,” in his words. They were always making stupid mistakes. They stayed on the airwaves for too long and repeated messages. One evening in July, the radio operator in Berlin transmitted the same message, “OK HELLO,” for fifteen straight minutes over the same frequency. Utzinger scolded Berlin: “The enemy has such an easy time!”

Gradually, Utzinger’s mood improved. By November 1943, the network seemed poised for a string of terrific successes. Becker assured him that it was almost time for the plotters in Bolivia and elsewhere to activate, the coups to be attempted. That month, Becker befriended a Chilean gunnery sergeant who had just returned from the United States after completing a one-year weapons course offered by the U.S. Navy. The Chilean’s descriptions of U.S. naval capabilities and tactics, relayed to Berlin over the radio, amounted to a detailed American game plan against Nazi ships and U-boats:

In day fighting, the heavy artillery is said to use the following manner of ranging fire: salvos every 7 seconds. The first salvo 300 yards over the distance, measured by radar. The second salvo the radar distance. The fifth and sixth salvos 200 yards shorter or longer than the fourth salvo. In night fighting, the ranging is carried out by ladder and radar . . . Each shell contains aniline compound which produces intensive coloring of the water, so that the location of the fire can be observed . . . Depth charges [against U-boats] resemble English Vickers [depth charges]. Models with 300 and 600 lb. of TNT charge. The fuze contains 3.25 lbs. of granular TNT . . . exterior depth setting for 30, 50, 75, 100, 150, 200, 250, 300 feet . . .

The spies wrote this message and the others with their Enigma, ALCSA JYFMK JFNVH KYOIM, transmitting the letters in Morse, dot-dash (A), dot-dash-dot-dot (L), dash-dot-dash-dot (C), not suspecting that in Washington, an American woman was sitting at a loom, spinning these ugly loops of letters into a sensible fabric of plaintext.

Becker and Utzinger thought they had everything wrapped up tightly. As far as they could see, there was only one major loose thread in their system, one element beyond their control: Osmar Hellmuth, the former insurance salesman, about to become a diplomat abroad.

During the final days of September, Becker handed Hellmuth a letter detailing some precision radio instruments they wanted him to purchase and bring back. He also gave Hellmuth several trunks containing sixty kilograms of gifts for friends in Germany. He radioed to Berlin that Hellmuth was on his way. “HELLMUTH enjoys the absolute confidence of the Argentine Government,” Becker wrote. “He is going to bring you lists of the government’s wishes . . . The Argentine Government demands strictest secrecy about the mission.” One last time, in Buenos Aires, the Hauptsturmführer wished his man luck, and on October 2, 1943, Osmar Hellmuth sailed into a faultless blue sea.

Elizebeth and her teammates solved the message about the Chilean sergeant who infiltrated the navy’s gunnery school and escaped with its secrets. They watched in real time as the confidential agents of Germany and Argentina conspired to flip the chessboard of global politics together. Thanks to the Cryptanalytic Unit’s successful assault on Circuit 3-N, Elizebeth understood the structure of Nazi espionage in South America. The money, the actors, the codes, the connections—she had the map now.

She forwarded her decrypts along the chain as fast as possible, often annotating them with brief written notes describing the named agents and explaining what they seemed to be doing.

Luna is probably Gustav Utzinger, the radio expert of the spy ring.

This is the latest in a series of messages dealing with the attempt of the German espionage ring, members of the Argentine general staff and the Brazilian integralists to form an anti-US bloc in South America.

These were ULTRA messages, stamped TOP SECRET ULTRA at the top.

By now, thanks to Elizebeth’s ULTRA decrypts and those of British codebreakers, everyone in the English-speaking spy world knew that Argentina was conspiring with the Nazis. The ULTRA messages were clear.

But they were also forbidden fruit. The Allies would have liked to show the decrypts to the Argentine government and demand that they stop. But then, of course, the Argentines would know that the Allies had broken the Nazi codes, and then the Argentines would tell the Nazis, and the lifeblood of ULTRA would instantly stop flowing through the world of Allied intelligence—a catastrophe.

There seemed to be no way out of this bind until October 1943, when Elizebeth solved messages from Circuit 3-N describing plans to dispatch an envoy named Osmar Hellmuth to negotiate a weapons deal between Germany and Argentina. This seemed to provide the Allies with an unprecedented opportunity. A relatively obscure Argentine man, this Hellmuth, was working very closely with Nazis, and he was about to get on a ship and sail to Bilbao, Spain. Perhaps he could be intercepted en route and forced to divulge his Nazi contacts. The Allies could say they got the information from the confession, not the Enigma messages that Elizebeth had solved. Then British and U.S. officials could finally take steps to disrupt the Nazi network in Argentina without exposing the ULTRA secret.

This plan required a bold and possibly illegal act by the British. Hellmuth was a diplomat. He had protections. He could not simply be kidnapped. Could he?

The British yanked Osmar Hellmuth off his ship in the middle of the night. They ignored his diplomatic privileges. They did not listen to his protests and did not allow him to make a phone call to his embassy. The Cabo de Hornos had been docked in the port of Trinidad before departing for Spain. The British placed Hellmuth on a different ship, bound for England. It sailed east across the Atlantic and arrived in Portsmouth, England, on November 12, 1943. From there the confused and indignant Hellmuth was carried to a secret interrogation facility in a mansion in southwest London called Camp 020, part of a network of nine interrogation centers operated during the war by MI5, British counterintelligence.

Argentine officials made frantic calls to British diplomats and asked where their citizen was. The British diplomats claimed they didn’t know.

He was placed in solitary confinement at Camp 020 for the first two weeks. The guards confiscated his seven trunks of gifts for German officials and the letter with the details of the precision instruments he was supposed to purchase. Then the prisoner was brought to see the commandant of the facility, Colonel Robin Stephens, a broad-shouldered man who wore the tan wool jacket of a British military commander, medals pinned above the left breast. A monocle affixed to his right eye made him look like a broken owl. His men called him “Tin Eye.” His motto regarding the art of interrogation was “truth in the shortest possible time.” He always said he did not believe in torture—he claimed he was so skilled at eliciting confessions that he did not need to use it—but after the war former Camp 020 prisoners told credible stories of being beaten by Stephens’s men, whipped, subjected to mock executions, deprived of sleep for long periods, made to stand in excruciating “stress positions,” and starved.

“I am speaking with authority,” the commandant told Hellmuth, “and full authority of Great Britain in war. My observations do not invite any replies from you and I shall regard any interruption as an incipient indiscipline.”

Stephens started to berate the prisoner. He said that the British had confiscated his letter asking him to buy precision instruments for the spies of the Reich, proving that he was a Nazi spy. He said Hellmuth was a Nazi stooge, in way over his head, playing a game he did not understand. Stephens made fun of the gifts in Hellmuth’s trunks: “There are about seven trunks of gifts. Food for the pot-bellied masters of Germany. Silk stockings for their clod-hopping women. Chocolates for their sniveling children.” Stephens said that Hellmuth’s only chance for escaping this facility was to tell the full truth and reveal everything he knew about the Nazi spy network in South America. “When you lie, we shall know instantly.”

Hellmuth stalled for a few days as the interrogators of Camp 020 demanded information. Initially the British found him to be “possessed, almost arrogant.” Hellmuth claimed he did not know much about SS intelligence activities in Argentina; he was familiar with one or two Germans from social circles and that was all. The interrogators asked about the man they knew only as “Sargo”—the man they suspected was “the head of Himmler’s faction in Buenos Aires” and “the prime mover of the secret mission.” The power behind the scenes, the Nazi mastermind in South America. Who is “Sargo”? What is his real name? What is his rank? Hellmuth said he did not know. He began so many sentences with the word probablemente, “probably,” that the interrogators became infuriated and banned him from saying it ever again.

Eventually, the interrogators said that if he didn’t start talking, his treatment in the camp “must necessarily deteriorate,” a hint he would be tortured.

Hellmuth softened. He told the British about how Argentina had worked with the SS to depose the Bolivian government and install a Nazi-friendly dictator. He told them about the clandestine radio stations and the radio technician who ran them, Gustav Utzinger, code name “Luna.”

Most important of all, Osmar Hellmuth divulged the secret that his British interrogators had been burning to know. Hellmuth’s confession, made possible by Elizebeth’s decryptions, would soon spark a fantastic chain of global events, forever turning the tide of the Invisible War in the Allies’ favor.

Who is “Sargo”?

Poor and unlucky Osmar Hellmuth, cold and alone, had been wondering for weeks if his personal sense of honor was worth this suffering, and now he decided it was not. “Sargo,” he told his captors, was Siegfried Becker, an SS captain, age thirty-two, five foot ten with a strong build and blond hair.