The idea of being able formally and categorically to identify criminals was gathering traction in various jurisdictions. Around the same time that Herschel was developing his system, a police clerk in Paris called Alphonse Bertillon was buckling under the volume of incoming prisoners. He decided to try to identify them systematically using anthropometry, the science of measuring humans. He chose eleven body measurements, including width of head and distances from elbow to end of middle finger. Bertillon put the odds of two people sharing all eleven of his measurements at one in 286 million. He recorded the individual measurements on file cards, and in the middle of the cards he stuck two photographs – full face and profile – and thus the mug shot was born.
Meanwhile, near Tokyo, a Scottish medical missionary started experimenting with fingerprints. Henry Faulds had noticed that ancient potters marked their pots with finger and thumb marks. He also discovered that subtle prints could be made visible when dusted with powder, and he used the technique to exonerate a man accused of burglary. When Faulds showed the real thief the similarities between his print and the one on a windowpane in the burgled house, he broke down and confessed. As a result of his observations, Faulds devised a method of fingerprint classification based on prints from all ten fingers. He tried to persuade Scotland Yard to set up a fingerprint department using his system, but he was rejected.
The Bertillonage record of twenty-one-year-old George Girolami, arrested for fraud
Undaunted, Henry Faulds wrote to Charles Darwin detailing his fingerprinting method. Darwin was intrigued by the idea but felt that it was work more suited to a younger man, so he passed it on to his cousin, Francis Galton. Galton spent ten years studying fingerprints and wrote the first book on the subject, Finger Prints (1892), in which he distinguished eight basic fingerprint patterns of arches, loops and whorls. He also demonstrated that every human finger fits into one of these categories in its own unique way.
After reading an article by Galton, Croatian-born police official Juan Vucetich began collecting the fingerprints of arrested men in Buenos Aires, Argentina. He devised his own ten-finger system of classification which he called ‘dactyloscopy’ – and which many Spanish-speaking countries still use today. As well as being used in criminal cases, it was quickly adopted by the Argentinian government as a form of verification on internal identity passes.
Vucetich’s system soon faced a demanding and disturbing test case. On 29 June 1892, in a village near Buenos Aires, 4-year-old Teresa Rojas and her 6-year-old brother Ponciano were found brutally murdered in their home. Their mother, Francisca, was alive but her throat had been cut.
Francisca told the police that her neighbour, Pedro Velázquez, had stormed into her home, murdered her children and tried to slit her throat. The police tortured Velázquez for a week, but he stuck to his alibi: he had been out with a group of friends at the time of the murders.
Frustrated at the lack of a confession, Inspector Commissioner Alvarez returned to the house. This time he noticed a brown patch on a doorframe, which he thought might be a bloody fingerprint. He removed the bloodstained section of wood from the frame and took it, along with fingerprints taken from Velázquez, to Juan Vucetich, who had just opened a fingerprint bureau in Buenos Aires.
Vucetich confidently declared that the prints did not match those on the doorpost. Then he took the prints of Francisca Rojas. They were identical. Faced with the damning bloody fingerprint evidence, the mother confessed to murdering her two children, cutting her own throat for effect and accusing an innocent man. She had wanted to improve her chances of marrying her boyfriend, who didn’t like children. Instead she became the first person to be convicted of a crime based on fingerprint evidence. She was sentenced to life imprisonment.
Following the Rojas case, Argentina abandoned Bertillon’s anthropometric system and began organising its criminal records on fingerprints alone. Soon, other countries began to follow suit. The following year, Edward Henry, the chief of police in Bengal, added thumbprints to his anthropometric criminal records. Although fingerprinting had been used officially in civil matters in Bengal since William Herschel had introduced the system forty years previously, the police had never taken advantage of it. Working with an Indian police officer, Azizul Haque, Henry improved on Galton’s system to produce one which allowed an investigator to use the physical characteristics of a fingerprint to create a unique reference number. These numbers were then used to file the fingerprints in one of 1024 pigeonholes in the police headquarters; when a new fingerprint was taken, its characteristics were coded, and the appropriate pigeonhole checked to see if it had been filed before. In 1897, the ‘Henry Classification System’ was adopted throughout British India.
In 1901 Henry was recalled to London to head the Criminal Investigation Department (CID) at Scotland Yard. He immediately set up the Fingerprint Bureau to record the identity of criminals in the belief that it would foil repeat offenders. Before there was a reliable system of recording their identities, it was common practice among career criminals to dodge a harsher sentence by making up an alias and pretending to be a first-time offender rather than a recidivist. In its first year alone the bureau cracked the pseudonyms of 632 habitual criminals.
As is often the case with new developments, it takes a sensational case to establish a new forensic technique in the public consciousness. For fingerprints, that leap into the forensic limelight came four years later, in 1905. On a Monday morning at the end of March, William Jones turned up for work at Chapman’s Oil and Colour Shop in Deptford High Street, London. The 16-year-old was surprised that, although it was half-past eight, the paint shop was locked and shuttered. The manager and his wife lived above the shop and they usually opened up for their early customers at half-past seven. William was concerned that they might be ill; at seventy-one and sixty-five, it seemed plausible. When knocking produced no response, William barged the door with his shoulder. It held fast. He stood on tiptoe and squinted through a gap in the shutters. At the back of the shop, by the fireplace, he could make out a lounge chair tipped on its side.
Anxious now, William ran to fetch a friend. Together they hurried back and broke the door down. William discovered his boss, Thomas Farrow, lying underneath the overturned chair, his bald head smashed open, blood seeping into the ashes of the fireplace. During the subsequent autopsy, the pathologist expressed the view that Thomas had been hit six times around his head and face, probably with a crowbar.
Sergeant Albert Atkinson was the first policeman on the scene and it was he who found Ann Farrow in bed upstairs, grievously battered and unconscious, but still clinging on to life. Atkinson noticed a moneybox lying open and empty on the floor by the Farrows’ bed. William explained that Mr Farrow normally took the box to the bank on Mondays to deposit the shop’s weekly takings of around £10.
Melville Macnaghten, Edward Henry’s successor as head of the CID, took charge of the case. On his first day at Scotland Yard, in 1889, Macnaghten’s new boss had briefed him on the unsolved Jack the Ripper murders of the previous year. For the rest of his career Macnaghten kept photographs on his desk of Jack the Ripper’s mutilated victims to remind him to try harder. Still, like any experienced detective, he had unsolved murders of his own. Just three days after he joined the CID, Macnaghten had found himself picking up pieces of a dismembered woman from along the riverbank. Her murderer was never found and the case became known as the ‘Thames Mystery.’
Macnaghten was determined to solve Thomas Farrow’s brutal murder. The crime had shocked local residents. Deptford was a polluted and crowded district. Disease and crime were facts of life. But cold-blooded murder was rare.
Because the elderly couple had been found in their night-clothes, and because the pathologist estimated Thomas Farrow had died not long before William discovered his body, the police believed that Thomas had been tricked into opening his front door early in the morning. They speculated that the assailant had attacked Thomas immediately, then run up
stairs to find his moneybox. Detectives found a pool of blood at the top of the stairs, so they deduced that Thomas had somehow managed to chase his attacker upstairs, where his wife lay unprotected. They concluded that the assailant had callously finished him off, silenced his wife with complete ruthlessness, taken the money and run.
Macnaghten examined the moneybox carefully and noticed a greasy finger mark on the underside of its inner tray. He picked the box up with his handkerchief, wrapped it in paper and took it to the Fingerprint Bureau. Macnaghten knew that he was risking public ridicule because, although fingerprint evidence had nailed a burglar, Harry Jackson, in 1902, it still had the taint of palmistry about it. Not everyone had been convinced by the efficacy of fingerprinting at Jackson’s trial. After hearing the guilty verdict, someone signing off as ‘A Disgusted Magistrate’ wrote a letter to The Times: ‘Scotland Yard, once known as the world’s finest police organisation, will be the laughing stock of Europe if it insists on trying to trace criminals by odd ridges on their skins.’
A CID assistant checks a new set of prints against Scotland Yard’s fingerprinting records in 1946
Charles Collins, head of the Fingerprint Bureau, looked at the tray with a magnifying glass and, from the size of the print and the slope of its ridges, recognised it as the right thumb of a sweating hand. He was also pleased to see significant differences when he compared it to the prints of Sergeant Atkins and the Farrows, which he had also taken. Those differences would strengthen the case against a suspect whose right thumb matched the print.
Although the bureau was only four years old, it had already amassed around 90,000 finger and thumbprints, stored in its enormous wooden cabinet of pigeonholes. Collins looked in the appropriate pigeonhole, but found no match.
The next blow to the investigation came five days later, when Ann Farrow died from her injuries. Macnaghten had hoped she would return to consciousness and describe her attacker.
Then there was one of those breaks that sometimes come detectives’ way thanks to the media. Having read about the murders in the press, a milkman came forward, saying that he had spotted two men leaving the Oil and Colour Shop at 7.15 a.m., and had shouted out to them that they had left the front door ajar. One of them had turned round and said, ‘Oh! It don’t matter’ before they had both walked off. The milkman described their appearance. One had a dark moustache and was wearing a blue suit and a bowler hat; the other was wearing a brown suit and a cap.
Then another eyewitness, a painter, came forward to explain why young William Jones had found the front door locked. The painter had glimpsed an old man with blood on his face shutting the door, at 7.30 a.m. Macnaghten reasoned that Thomas Farrow had somehow survived a second battering, this time at the top of the stairs, and, in a state of deliriousness, had staggered downstairs and closed the door, before moving to the back of the shop and finally succumbing to his wounds.
A third eyewitness came forward: a woman who had seen two men matching the milkman’s description running down Deptford High Street at 7.20 a.m. Even better for the police, she recognised one of them. The man in the brown suit, she said, was 22-year-old Alfred Stratton. The descriptions of his companion matched that of Alfred’s 20-year-old brother, Albert. When the police went to question Alfred’s girlfriend, she admitted that the day before the murders Alfred hadn’t had enough money to buy food; but that the day after, he had come back with bread, bacon, wood and coal. This was enough for Macnaghten. The Stratton brothers were arrested a week after Thomas Farrow’s murder.
But the ill luck that had dogged the investigation continued. Neither the milkman nor his assistant was able to pick the Strattons out in an identity parade. The brothers were filled with bravado; they joked that, when Charles Collins took their fingerprints, it tickled them.
Collins had the last laugh, however. When he examined the fingerprints, he found the mark on the moneybox matched Alfred Stratton’s right thumb.
Still the prosecution knew they had their work cut out. Could a one-inch sweat mark persuade the jury? So much hung on this case: the conviction of a pair of cold-blooded killers; the restoration of the reputation of Scotland Yard, so damaged by Jack the Ripper’s murders; and the acceptance of fingerprints as key evidence. Both Macnaghten and the Metropolitan Police Chief, Edward Henry, understood how much was at stake.
Ironically, Henry Faulds, back from Japan, was ready to testify for the defence. He had his own axes to grind. First of all, Scotland Yard had rejected his calls to set up a fingerprint bureau. Then it had opened one up based on the Henry system, and refused to acknowledge Faulds’ part in the development of fingerprinting. Faulds was intent on claiming that not enough research had been done to prove that a print from one finger could identify an individual beyond doubt.
Charles Collins took the stand, several blown-up photographs under his arm. He showed the jury the smudged print taken from the moneybox, then the perfectly crisp prints of the Farrows and Sergeant Atkinson. The jury didn’t need much explanation to see that the prints were different from each other. Then Collins produced Alfred Stratton’s thumbprint. The similarity was immediately obvious. Collins pointed out eleven separate points of similarity. The jurors were mesmerised.
When the defence cross-examined Collins he argued cogently that no two prints from the same finger are ever exactly the same, because of differences in the pressure and angle of contact. That was just as well, for, when the first fingerprint expert for the defence, John Garson, took to the stand, he proceeded to discredit Collins’ eleven points of similarity. The distances between the points were slightly shorter in some and longer in others, he said. And the lines curved a tad differently as they reached the points.
Buck Ruxton’s fingerprints, taken in Liverpool Prison, 1936
The eminent counsel for the prosecution Richard Muir started his cross-examination of Garson by placing two letters down in front of him. They had both been written by Garson on the same date. Garson had written one to the Stratton lawyers, offering to testify for them. The other was to the Director of Public Prosecutions, making the same offer. Muir’s implication was that Garson was a hired gun, willing to sell his services to the highest bidder. To this charge, Garson replied, ‘I am an independent witness.’ To which the judge added sternly, ‘An absolutely untrustworthy one.’ Garson got down from the stand with his credibility in tatters.
Henry Faulds was due to give evidence next. He was ready to deliver his devastating view that, after comparing many thousands of fingerprints, he could not definitively say that a single fingerprint could only belong to one person on earth. But the defence panicked lest Muir would undermine him as successfully as he had Garson. Faulds never got to speak.
After a two-hour deliberation, the jury came back with a guilty verdict. On 23 May 1905, nineteen days after their trial had begun, the Stratton brothers both went to the gallows. The British judicial system had stepped into a whole new realm of scientific evidence.
By 1905, fingerprint bureaus had been established in India, the UK, Hungary, Austria, Germany, Switzerland, Denmark, Spain, Argentina, the US and Canada, but their evidence had so far only been used as proof of guilt in Buenos Aires and London. The Stratton case demonstrated how powerful this evidence could be. In 1906, the year after that keynote trial, four other British men were prosecuted based on crime scene prints. In the same year, the New York City Police Department (NYPD) introduced fingerprinting to police departments across the US.
Edward Henry’s system of classifying and finding matching prints remained essentially unchanged until computers led to the automatic fingerprint identification system in the 1980s. And so has the work of the fingerprint examiner.
First of all an examiner needs to understand what they are looking at. The pads of our fingers are home to intricate patterns of ridges and valleys. If we coat one of those pads with ink and press it on to a piece of paper, the resulting ridge pattern is instantly recognisable as the iconic image of a fingerprint. Our f
ingerprints are part of us from before birth; they first appear in the tenth week of pregnancy, when the foetus measures only 8 cm. As one of the three layers of tissue that make up the foetus’s skin – the basal layer – starts to grow at faster rate than the other two, ridges form to relieve the resulting stresses, ‘like the buckling of land masses under compression’. If your finger pads were flat, the pressure on the skin would be equal and the ridges would be parallel. But because finger pads slope, ridges form along lines of equal stress, most usually in concentric circles. Ridge patterns also appear across the palms of our hands and on the bottoms of our feet. Other primates have them, too, and evolutionary biologists believe there are good reasons for them. They help our skin to stretch and deform, protecting it from damage; they create valleys down which sweat can escape, reducing slipperiness when we hold things; and they give us more contact (and hence grip) with rough surfaces like tree bark.
When we touch a surface with a finger, the ridges leave their unique pattern on it. Even the prints of identical twins differ. In all the years that fingerprinting has been practised, no one has yet found two identical clear and complete prints belonging to two different fingers.
To identify people from the marks they leave behind is simple enough in a family setting. These small muddy prints belong to the toddler who forgot to take his shoes off. Those even smaller ones are the dog’s. But deductions like these are made from a small number of possible culprits, and the prints in question are patent – visible to the naked eye. Invisible, latent prints are much trickier. Substances like sweat, mud, blood and dust can produce both patent and latent prints. The more absorbent or irregular the surface, the more difficult it is for a CSI to get a good print. Though it was once impossible to take prints from plastic bags or human skin, the technologies have improved and there are now ways to do it.