In the conference room off the hangar at Joint Base Andrews, I looked at the president and the country’s leaders and saw them all studying me.

I said, “If I had unlimited resources, I’d bring in the best investigative coordinator the FBI has to oversee four distinct teams. One team should focus on forensics and generating swift, accurate test results. The second team should be composed of the Bureau’s best investigators dispatched into the field, starting at the three assassination sites. Intelligence analysts from the FBI, CIA, NSA, and Homeland Security should staff the third team and should have an eye on every piece of evidence that comes in.”

President Larkin nodded. “And the fourth?”

I said the last team should be composed of a smaller group of elite investigators, analysts, and forensics specialists assigned to look at the crimes from a loftier perspective. What was the purpose of the assassinations? Why did they have to happen? Whom and what did they benefit? Whom and what did they destroy?

Mahoney agreed with my rough design but added, “That fourth team should also be charged with identifying and arresting the person or persons in government who helped coordinate the attacks.”

There was dead silence in the room.

Finally, Director Sanford said, “You believe there’s a traitor, Agent Mahoney?”

“Without question, sir,” Ned said. “Probably several.”

An older man with a professor’s manner whom I later learned was NSA director John Parkes leaned forward and said, “Or whoever is behind this has completely compromised our cybersecurity system. You’ll want to consider this as well.”

Parkes typed on a laptop. A screen on the wall flashed, then showed a map of the world with continents and countries connected by strands, streams, and rivers of tiny shimmering lights.

Parkes said, “You’re looking at the data flow on the dark web forty-eight hours ago, then twenty-four hours ago, and now.”

The lines of sparkling light ebbed and flowed. Roughly thirty-six hours ago, a big dense river of data connecting the United States, Russia, North Korea, and China had appeared, then widened and deepened, building toward a flood.

Linda Johnson, the Senate minority leader, said, “Are we looking at the start of World War Three?”

Before anyone could reply, Director Sanford looked at his phone, said, “Abbie Bowman’s assassin was killed ten minutes ago. New York rookie cop shot him. He was carrying perfect forgeries of Treasury Department IDs. They’re fingerprinting him and checking dental records as we speak.”

Mahoney said, “That’s a big break.”

“Here’s another,” Felix White, the CIA director, said, gesturing at his laptop. “We’ve picked up satellite chatter, Russian satellite chatter. Three-quarters of the Kremlin think the motherland is behind the assassinations.”

“Maybe it is,” I said. “Maybe through Viktor Kasimov.”

“Son of a bitch,” White said, and he threw a pencil on the table. “We keep an eye on Kasimov when he’s not here assaulting women. We were alerted this morning that his pilot filed flight plans to London. Kasimov and his crew took off around nine.”

“Right before the shooting started,” General Hayes said.

President Larkin said, “Have our agents waiting for Mr. Kasimov at Heathrow. I don’t give a damn about his diplomatic status. The second he touches down, grab him and put him on a return flight in handcuffs and ankle irons.”

“Yes, Mr. President,” the CIA director said. “With great pleasure, Mr. President.”

There was a soft knock at the door. It opened, and a flustered air force captain said, “Excuse me. There’s a Keith Karl Rawlins, an FBI contractor, who just landed from Quantico. He says he might have figured out who shot the president.”