A police constable investigating a burglary at a crockery warehouse in the Clerkenwell district of London one September night in 1909 made a gruesome discovery. The warehouse yard was protected by a high wooden gate with a row of iron spikes along the top. As the constable flashed his lamp along the top of the gate he caught a glimpse of something very strange attached to one of the spikes. He clambered up to take a look. The strange thing was a finger-a little finger-held firmly in place by a gold ring.
Peering over the gate and into the yard he could see blood on the ground. It wasn’t hard to fathom what must have happened. In jumping from the gate, the burglar had caught a ring on the little finger of his right hand on the tip of the spike. The weight of his body had torn the finger clean off. The constable removed the digit and sent it for fingerprinting.
WHEN it comes to identifying criminals, today’s sleuths are spoilt for choice. They can take their pick of voice prints, iris patterns and DNA analysis-and they have powerful computers to search huge databases for a match. Back at the end of the 19th century, fingering a felon was a tougher proposition. In the 1880s the state-of-the-art ID kit was a box of instruments designed to measure various bits of a crook’s anatomy. This kit was put together by Alphonse Bertillon, chief of criminal identification for the Paris police force.
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Bertillon, the son of an anthropometrist, reasoned that a photograph plus a selection of key measurements would make an ideal system of identification. With calipers and other precise measuring devices he would record criminals’ heights, the breadth of their skulls and the length of their feet, fingers and several other parts of their bodies.
The British and American police adopted the French system, and soon police officers in all three countries were jotting endless measurements on a specially designed form. But there were snags. Measurements could vary depending on how tightly the callipers were pressed. And some human dimensions change: age withers even the brawniest of villains, for instance. The advent of fingerprinting must have come as a relief to policemen bored with recording their suspects’ inside leg measurements.
The fingerprint branch of the Metropolitan Police opened for business at its Scotland Yard headquarters on 1 July 1901. The idea of using fingerprints for identification was hardly new. Nor was the realisation that prints could be classified. The Czech physiologist Jan Purkinje had suggested as much in 1823, and gone on to identify nine varieties-although he hadn’t been thinking of collaring crooks at the time.
In the 1870s, Henry Faulds, a British surgeon working in Tokyo, devised a system of classification using inked impressions of people’s fingers. He passed his findings on to Charles Darwin who forwarded them to Francis Galton. Drawing heavily on Faulds’s work-or, if you want to be less charitable, appropriating it-Galton defined the familiar loops, whorls and arches.
Under Galton’s system, each finger was labelled an L, W or A, depending on the predominant print pattern. The resulting sequence of letters could be filed alphabetically. It was crude, and searching for a match was an arduous job-and increasingly lengthy once the prints began to pile up.
By this time, Edward Henry of the Bengal Police had begun working on a way of speeding up the process. He devised a formula for allocating any set of prints to one of more than a thousand categories. He divided all prints into two broad groups-loops with arches, and whorls with compounds (combinations of two or more of the others). He then divided the fingers into pairs, and gave each a number according to which pattern predominated on which of the two fingers. This created 1024 possible groups.
Anyone trying to match a new set of prints with one on file could use Henry’s rules to go straight to the right group. Only then would the detailed scrutiny have to begin. Because of the need for various sub-classifications, the system was actually rather more complicated than this. But Scotland Yard adopted the Henry system in 1901-and the rest of the English-speaking world quickly followed suit.
As with all new technology, enthusiasts needed to prove the system’s worth to win over the sceptics. It didn’t take long. Over the next few years, Scotland Yard notched up a string of successes that established fingerprinting as the definitive method of identifying criminals.
Fingerprints made their court debut in 1902. When burglar Harry Jackson broke into a house and stole the owner’s billiard balls he left his mark on a freshly painted window sill. He became the first suspect ever linked to the scene of a crime by a fingerprint. He was jailed for 7 years.
Three years later, the police achieved their first murder conviction based on fingerprint evidence. Two masked men robbed a shop in Deptford High Street, attacking and killing the shopkeepers. Police discovered a single thumbprint on the tray inside the cash box. When suspicion fell on the Stratton brothers, Alfred and Albert-the police found that Alfred’s right thumb matched the print on the tray. The brothers were hanged.
Fingerprints also scotched the criminal careers of the notorious Fox brothers, identical twins who’d got away with a series of crimes in which one would establish an alibi while the other would commit a robbery. The police never knew which one to charge. Fingerprinting put an end to the scam because even identical twins don’t have precisely the same prints.
The peculiar case of the Clerkenwell finger brought the fingerprint bureau yet another first: this was the first time the police had been called on to take a print from a detached part of the body.
After taking a print, the fingerprint experts began to search their files. They were lucky: the print matched one already on file. It belonged to a man with several aliases, but whose real name was thought to be William Mitchell. As no one had any idea where to find the elusive Mitchell, that might have been as far as the investigation went-had it not been for a stroke of luck. One month later, a detective from another station arrested two pickpockets working the tram queues in south London. One of the men, who called himself Harry May, protested his innocence rather too loudly.
The Morning Leader of 19 October reported what happened next. “At the police station, drawing attention to his right hand which was heavily bandaged, May asked, ‘How could I pick pockets with a hand like this?'” Curious about May’s wound, his captors asked to see it-upon which May revealed the stump of his missing little finger. At the sight of the stump, one of the detectives recalled an item in the Police Gazette describing the Clerkenwell finger. He called in the Yard’s fingerprint branch. The remaining nine of May’s fingers matched nine of the ten on file as belonging to Mitchell.
Mitchell was charged under the Prevention of Crimes Act, and sentenced to 12 months hard labour. He had, you might say, been well and truly fingered.