Although science is still unmasking the chemical, genetic and physiological mysteries behind the miracle that is our fingerprints, society has managed to make use of these marks in areas such as criminology for centuries. Even though we didn’t know why, it was clear that fingerprints were something special.
Who first discovered that fingerprints were a credible means of proving someone’s guilt in a murder case? What scientific method irrevocably determined a match between two prints? The story of dactyloscopy, the science of fingerprint identification, dates back several centuries to ancient China, around 300 AD, when fingerprints were used as evidence in theft trials.
A series of small steps
Following the invention of paper in China (105 AD) it became common practice to stamp a finger or palm print on each page of official documents using ink. Dactyloscopy has since travelled a long road from east to west, with numerous individuals making discoveries along the way, each adding their grain of sand to help pave the way to our modern science:
- Sir William James Herschel, considered the first European to understand the potential offered by fingerprints to identify individuals, was a British Army officer stationed in India, who in 1850 began including fingerprints in contractual documents.
- Henry Faulds, meanwhile, was on a mission as a doctor in Japan when he began collecting fingerprints from humans and monkeys. Having conducted his own specific study, in 1880 he sent a letter to the famous naturalist Charles Darwin, suggesting that fingerprints were unique, classifiable and permanent. That same year Herschel became the first person to publish a paper in a scientific magazine on the use of fingerprints to identify individuals.
- Alphonse Bertillon was working as a policeman when he developed his anthropometric identification method, or the Bertillon method. Anthropometry uses an individual’s body measurements as a means of identification, based on the premise that no two individuals have identically matching body measurements. However, over time the method became discredited as a reliable approach to identification, despite Bertillon being appointed Head of the Judicial Identity Department.
- Sir Francis Galton was another eminent scientist who made a contribution to solving the mystery of fingerprints. Nephew of the famous Charles Darwin, his research focused on hereditary issues. He used anthropometry to find several correlation coefficients (measuring the degree of correlation) in the human body. He also went down in history as the first author to publish a book on the subject of dactyloscopy, “Fingerprints” 1982, in which he demonstrated that fingerprints are unique and irreplaceable.
The litmus test
Juan Vucetich, Croatian-born but nationalized as Argentinean, worked at the Central Police Department in La Plata when he first took an interest in the work published by Francis Galton. He then personally developed a method to match fingerprints, which he put into practice in 1891 when he collected sample fingerprints from 23 prisoners.
In 1892 Vucetich worked with the Buenos Aires police on a homicide case in which two children had been murdered. The initial investigations pointed to a man related with the children’s mother, but investigators were unable to obtain a confession despite employing a number of torture techniques. A fingerprint had been found at the crime scene, stamped in blood. Vucetich proved that the print belonged to the children’s mother, Francisca de Rojas, who, confronted with the evidence, confessed to the double homicide.
Just 6 years after Vucetich first made use of an effective fingerprint identification mechanism, the Paris Academy of Sciences publicly acknowledged it as the most efficient means of identifying individuals known to date.
Fingerprints have since transcended the field of criminal investigation, and are now established as an everyday means of identification, so much so in fact that you may use your fingerprint to unblock your smartphone. New technologies have fine-tuned the print comparison process, and despite ever more precise tools emerging, science continues to show evidence that these marks are personal and inalterable. A look at the numbers helps demonstrate the important organizational role that fingerprints play in many societies. In the United States the IAFIS (Integrated Automated Fingerprint Identification System) processes an average of 63,000 fingerprints every day, according to official sources. Criminal background checks run when an individual applies for a job or tries to buy a firearm in certain states of the USA mean that citizens are forced to permanently register their fingerprints in the national system. Paradoxically, new technologies also mean that the identities that fingerprints serve to verify have also become common currency for cybercrime. Warnings have even been made against posting photos on social networks in which prints are visible. Do our fingerprints need to be protected more carefully?