If you make any kind of contact, you will leave a trace. In a high-tech world, even so much as a molecule left behind will be enough to confirm your presence. It’s easy to assume that crime-scene analysis is a very modern area of detective work, but the principle was actually formulated in 1904, by a scientist called Edmond Locard. ‘Every constant leaves a trace’, he said, thus inaugurating the discipline of forensics. From mud on shoes to fibres on chairs, any evidence drawn from the crime scene, anything that the transgressor touched, would bear some trace of his person. It was almost as though Locard could see the microscopic DNA-dominated future. In any case, detectives, whose job it is not merely to envisage and imagine crime scenes, but also to deduce the identity of the participants of those scenes, have always been keenly interested in the physical tokens that can help point to guilt.
For instance, a fingerprint found in 1902 in a billiard room in a smart house in hilly suburban London helped secure the conviction of a serial burglar using magnifying glasses and up-to-the-minute photography. This was the very first time that such prints were used as evidence in the Old Bailey. The thief had made off with all the billiard balls; but had left a particularly clear set of fingerprints on the window-sill.
Slightly stranger was the 1950s case of the bare footprint on top of a television set, which led to a surprise conviction. The scene of the crime: the fourth-floor flat of Mrs Bowles. Before retiring to bed, Mrs Bowles had left her newly washed underwear out to dry on the mantelpiece. Since her flat was sixty feet up, and presumed burglar-proof, she had left the window slightly open. But this serial burglar was a skilled climber and it was the underwear that he chose to take. Even more bizarrely, he committed the crime in bare feet. This was the first time such a print had been used in court.
These cases on their own might not sound like triumphs of technical wizardry, but the fact is that under either the hiss of gaslight or the pitiless glare of modern LED spotlights, Scotland Yard has always been consistent in its enthusiasm for scientific innovation.
In fact, nowadays, a crime scene is a laboratory. Everything must be handled with care so that the conditions remain in a state of perfect equilibrium. And this laboratory–the scene of a daring heist or a shocking attack–is one in which the tiniest molecules serve to build a picture of human passion and intrigue. Clues are pieced together from a single strand of hair, an atom of paint from a location far off or a fragment of clothing.
The puzzles in this section are inspired by the breathtaking leaps in scientific understanding that have been made by the experts at Scotland Yard. From the simplest magnifying glasses to the very structure of DNA, these puzzles celebrate the dazzling armoury of technological advancement that detectives have been able to deploy. These new inventions do not reduce or replace the detective’s innate brilliance at weighing and understanding the souls of suspects, rather they complement such understanding.
A fascination with the idea of guilt being imputed by invisible tell-tale signs stretches right back through the centuries. From thirteenth-century China, a book entitled The Washing Away of Wrongs made its way to the West along the Silk Road trade route through central Asia and, once translated, its ideas were instantly influential. From the careful examination of bodies and wounds, to methods for narrowing down rural suspects by testing whose sickle attracted the most flies, and therefore carried traces of blood, this was a text that stressed impartiality and an open mind when approaching suspected homicide. In the fourteenth century, the European rediscovery of this text led to autopsies being carried out in Bologna. This was the first effort made by dispassionate observers in the western world to locate and prove the cause of death. At a time when investigations of dead bodies carried a sharp frisson of religious sensitivity and danger, these autopsies were radical acts, but fascination with the disposition of the dead continued.
In a similar vein, the minute examination of everything from hair to teeth commenced with the arrival of the microscope in 1590. Its invention is broadly credited to father and son Hans and Zacharias Janssen. Owing to the astounding cost and expertise involved with working with glass, it was a long time before the study of optics could spread wide enough to have any impact when it came to crime. Yet the idea alone was sufficient to open minds to the world beyond the naked eye.
The greatest jump forward came in the 1670s from Antonie Van Leeuwenhoek with his self-designed single-lensed microscopes. This Dutchman took intense delight in subjecting samples from his own body to scrutiny, from fragments of tooth plaque to even less palatable items. This sparked a nineteenth-century hobbyist craze of seeing the weirdly animated world of any sort of fluid sample; something Leeuwenhoek termed ‘animalcules’. Leeuwenhoek–who came to be honoured by the Royal Society in London–had opened up an entire realm in miniature: from bacteria to muscle fibres to spermatozoa. By doing so, he helped to revolutionise the way that the human body and each of its own individual signifiers, from red blood cells to capillaries, were seen. Every body could now be understood in terms of its own microscopic uniqueness.
Meanwhile, the study of fingerprints–which has somehow come to symbolise the entire business of detection–was adopted surprisingly slowly by Scotland Yard. By the 1860s, William Herschel, working with government officials in India, had come to see the individual properties of every single fingerprint. In a few cases, this led to them being used as legal identifying marks on documents requiring such proof. But for the detectives, there were two obstacles: first, the conclusive proof that fingerprints really were wholly unique, and second, the means by which to obtain them. Not every crime would handily feature prints left on a clear glass tumbler!
There was some competition in finding a way to uniquely identify suspects. In 1880s France, an anthropologist called Alphonse Bertillon constructed a new system that involved taking all the body measurements of offenders and suspects; the idea being that all of these elements together would create a unique profile. Meanwhile in Britain, the slightly less labour-intensive method of collecting fingerprints was given a boost by another anthropologist. Sir Francis Galton, a relation of Charles Darwin, wrote with a fresh authority about the absolute individuality of fingerprints, and by 1901, Scotland Yard was confident enough in the evidence to begin a proper classified register of fingerprints from convicted offenders.
Chemistry is another key element in the science of forensics, and it found its own uses as early as 1836. This was just on the cusp of what might frivolously be described as the golden age of Victorian poisoning: a period when the most remarkable proportion of murders seemed to involve the procurement of something lethal from the apothecary. It was James Marsh who formulated the first ever test for arsenic poisoning. In the years that followed, a cornucopia of new tests were devised for an ever-widening range of lethal elixirs.
Inspired by this poisonous period of history, Agatha Christie, the world’s best-selling crime novelist, made close studies of poisons, their effects and the means by which they may be detected. Hence the unusually high instance of this form of murder in her novels.
Chemistry tests to determine between animal and human blood took a little longer to become in any way reliable. This proved a source of frustration in some late-nineteenth-century cases where splashes of blood–presumed to be that of the victim–could not convincingly be used as evidence. Perhaps even more maddeningly for Scotland Yard, the author Arthur Conan Doyle gave his newly created detective a wildly unfair advantage; Sherlock Holmes had conveniently devised such a blood test in his fictional world. But perhaps Holmes was an inspirational spur. By 1900, the matter had been remedied, and indeed by that time different blood groups were identifiable too.
Holmes may also have been highly influential in other forensic matters, such as his method of identifying mud on a protagonist’s shoe that could pinpoint precisely where in the country the shoe had been. The Yard did not care to cite Holmesian tricks as their inspiration, but French forensic genius Edmond Locard, and professors such as Charles Tidy who habitually helped the Yard, were happy to do so. They devoured the adventures of The Great Detective.
Edmond Locard, for his own part, was fascinated by the crime-solving properties of dust. He recognised that dust had a number of origins and if correctly analysed, could reveal some extraordinary surprises about who had been where. The principle of it, avowed another forensic pioneer, Dr Hans Gross, was quite simple. ‘The dust of a ballroom’, he said (by means of example), ‘crowded with people, will in great measure proceed from the fibres from which the cloth of the dancers is woven’.
Locard–and his Scotland Yard admirers–took the principle a little further. He was gripped by the variety of these ‘mute witnesses’, the ‘microscopic debris’ that testified, ‘sure and faithful’ to ‘all our movements and encounters’. To him, there was something poetic in all the different sorts of dust, even down to the dust of dead butterflies, which fascinated him.
With these advances in detection, the men and women of the Yard were able to peer into the darkness of another realm, and experts, such as Professor Charles Tidy, were able to take them even further. In studying prone bodies of murder victims, lying where they fell, Professor Tidy could suggest what had happened, when, and at what angle. He could replay the sequence of events through looking at the shapes of the body’s muscles pressed against the floor and the positions of tiny objects all around it. Each small detail gave away a part of the story.
A further tool–with distinctly macabre overtones–was given a terrible global fame by Scotland Yard in the autumn of 1888. What marked the hideous Jack the Ripper murders out was not just their terrifying savagery but also the imagery of those foggy Whitechapel streets that remains so prevalent today. But it was a new police tool that gave the case a further gruesome immortality: the pioneering use of photography. The victims, unknown in their poverty, acquired grisly posthumous celebrity with the portraits the Yard took of their mortuary table faces. Just a decade or so later, the French had perfected the techniques of photographing crime scenes. These dreadful black and white tableaux of slain bodies in hallways and boudoirs were so shocking they were later displayed in upmarket galleries and at prestigious exhibitions as fully fledged works of art.
On a practical level, the emotionless gaze of the lens was able to freeze in time all the tiny particulars that, in real life, were acquiring dust and contamination minute-by-minute.
Perhaps the figure who made the most lasting contribution to this new science of analysing crime scenes was a forensic pathologist who was to become a household name. Sir Bernard Spilsbury–who as we shall see was instrumental in solving some of the more lurid cases in the Yard’s history–worked with detectives in formulating what were jocularly referred to as ‘murder bags’ but known properly as ‘detective boxes’.
This was standardised equipment that detectives would use when approaching the scene of a horrible murder: a leather bag containing rubber (later plastic) gloves, tweezers (for handling minute objects), brushes, tape measures and evidence bags (for careful preservation of objects). This equipment became essential after Sir Bernard Spilsbury had seen policemen at crime scenes picking up all sorts of evidence with their bare hands; it would not do.
The principle of the murder bag remains the same today, even if the means of analysing the evidence collected is super-advanced. Sir Bernard Spilsbury laid the foundation stones of conserving evidence, alongside his developments in tissue analysis and other tests. He was the pathologist called to a darkened house on Hilldrop Crescent in 1910, in the sooty north London suburb of Holloway where deep in the cellar were found buried human remains; meanwhile, the house’s occupant, one Dr Hawley Crippen, had made for the docks with his lover, and was on board a ship to America.
Sir Bernard, according to some accounts, was able to identify the grisly cellar discovery as Dr Crippen’s wife by means of a tiny distinguishing mark on a small patch of skin.
The capture of Dr Crippen was–incidentally–a technological coup for Scotland Yard at the time. He was on board a ship called the Montrose with his lover disguised as a boy. It is perhaps little wonder that they were recognised by the captain. Thanks to advances in telegraphy between ships and back to London, plans were formulated to arrest Crippen before he could make land in the US, which was beyond the reach of British justice.
The ship’s route took it through Canadian waters, making a number of stops on its way to the US. At the same time, the Yard’s Inspector Dew was on board a steamship, sailing at full pelt across the Atlantic in pursuit. After another frantic flurry of shipboard telegrams, Dr Crippen’s boat drew close to Quebec along the Lawrence river, and the ship was met with a team of pilots. Among them, in disguise, was Inspector Dew. And now, in the waters of a British dominion, he had his man. ‘Good morning, Dr Crippen, do you know me?’ he said. ‘I’m Chief Inspector Dew from Scotland Yard’.
Sir Bernard Spilsbury was also key to the unravelling of the creepy ‘Brides in the Bath’ crimes. The mystery began in 1915, when a boarding house owner in the north was reading the News of the World and was struck by a story about a wife in Highgate, north London, who was found drowned in her bathtub. The husband had collected on the insurance. This boarding house owner was amazed because exactly the same tragedy had unfolded in his house two years previously. The husband had a different name; but he sent the newspaper clippings to Scotland Yard, convinced of a connection.
Detective Inspector Neil, intrigued, visited the house in Highgate and discovered that the bathtub in question was rather small, and that the deceased wife was rather portly. Here was a mystery: even if she had had a seizure or epileptic fit, how then could her head have become completely submerged? There was no room for natural manoeuvre. Meanwhile, a detective in Kent got in contact to say that there had been a near-identical incident in Herne Bay; a wife found drowned in her bath, and a cashed-in insurance policy.
The husbands in question were called Henry Williams, John Lloyd and George Smith. But they were in fact all the same man: a serial bigamist (George Smith was his real name) and as it seemed, a serial murderer too. It was down to the pathologist Sir Bernard Spilsbury to work out how all the wives were drowned, especially in the instance where the bathtub was so small. In a striking piece of active detective work, with Sir Bernard’s advice, Inspector Neil hired several women volunteers who were experienced at diving. They donned their bathing suits and were invited to clamber into a specially-provided Scotland Yard tub. Inspector Neil tried pushing them under the water but the struggles and the noise–and indeed the failure to keep the women submerged–ruled that approach out. Spilsbury advised an alternative method, so Neil grabbed the ankles of one volunteer and pulled her head swiftly under the water; she lost consciousness almost instantly.
Sir Bernard’s theory that a cranial nerve, when subjected to sudden submersion nasally and orally, could cause the victim to faint and thus to drown, was correct. The diver was revived, George Smith was convicted and the case was closed.
Sir Bernard approached other cases with distinct Holmesian flavourings: a solicitor who murdered a rival with a box of chocolates (the soft centres carefully injected with arsenic); and a Leighton Buzzard murderer identified by means of soil analysis, where the specks of mud in his trouser turn-ups matched the soil of a certain field where the crime took place.
From all of this, detectives became the archaeologists of crime. They knew that something as small as a burnt matchstick in an ashtray could open up entirely new avenues of exploration. Long before the crime scene became a modern circus of white tents populated by professional operatives in baggy white suits, Scotland Yard’s finest were treating the scenes of murder like temples, in which nothing may be disturbed, and in which the past could be summoned and the guilty revealed.
And for detectives everywhere working on the molecular level, this is not merely about finding key details, but also about an entirely different way of looking at the world. Nothing can be taken at face value; everything, including the finest dust, must be interrogated for its true significance. Given the formidable armoury of scientific wizardry available now, one could be lured into mistakenly thinking that the art of detection can be handed over to computers. For surely a sample of soil and a single drop of blood, processed by artificial intelligence, would instantly find the culprit in a population of sixty-six million? In addition to this, all the software that can now not only recognise faces, but also individual gaits (the way we walk is almost as unique a signifier as fingerprints) must surely mean that no villain could ever escape justice?
Yet the world is much stranger and much more unpredictable than that. Even armed with DNA sequences drawn from crime scenes detectives must still ponder the mysteries of motivation, and the secret passions–hatred, envy or unrequited love–of the human heart.