First murder solved by a fingerprint

A historical Argentinian homicide

Warning: contains references to child murder

In 1892, the double murder of two children in Argentina was the world’s first ever successful investigation of a homicide using fingerprinting. Despite its significance, this tragic event is not well known. I came across this landmark case while researching the history of fingerprinting, and I decided to investigate further especially, as a Spanish speaker, I was interested in reading copies of the original reports on the case.

On 29 June 1892, in the suburbs of Neocochea, a city in the south-east of Argentina in the province of Buenos Aires, Ponciano Caraballo and his neighbour Ramón Velásquez came upon a terrible scene in the bedroom of the Caraballo family home. Lying on the bed were his two children, Ponciano Ernesto, aged 6 and Feliza, 4, together with their mother Francisca Rojas de Caraballo – their throats had been slit. The siblings were dead, but Ponciano’s wife was still breathing. Her injuries were superficial and she was soon able to reveal what had happened.

A terrible act

Francisca, who had been married to Ponciano for four years, claimed that she and her children had been attacked by their neighbour, agricultural labourer Ramón Velásquez. He had tried to seduce her and when she had refused, he had threatened to kill them all. She later changed her testimony and claimed that Velásquez had been attempting to take her children away from her, on her husband’s instructions, as he was going to leave her. Whatever the truth of the relationships, Ramón Velásquez was arrested on suspicion of murder.

According to the standard practice at the time, the local police used torture to attempt to extract a confession from the accused. Velásquez was subjected to several brutal beatings, and was forced to spend a night locked in a cell with the children’s bodies. Also, a police officer dressed up as a ghost entered the cell and tried to scare the prisoner into confessing. Despite these violent and intimidating interrogations, Velásquez refused to confess and professed his innocence throughout. Unsure of what to do next, the local police requested help from the force in the provincial capital, La Plata, and Inspector Eduardo Álvarez was sent to Neocochea to investigate.

The investigation begins

As soon as Inspector Álvarez examined the crime scene, his suspicions were aroused. Firstly, the bedroom door had been barred from the inside with a shovel, suggesting that the killer had not left the room by the door, as originally thought. Francisca claimed that Velásquez had struck her with the shovel, but there were no marks on her body. The murder weapon was a kitchen knife and Inspector Álvarez surmised that a labourer, such as Ramón Velásquez, would have been more likely to have used the knife that he carried on his belt for his daily work, rather than a kitchen implement. The senior police officer also found a soiled rag in some shrubs by the well outside the house, which he thought had been used by the perpetrator to wipe their hands.

The right thumb print taken by Inspector Álvarez in 1892.

The key piece of evidence, however, was a brown mark that Inspector Álvarez spotted on the bedroom window, which turned out to be a bloody thumb print. The officer thought it looked like the print from a woman’s hand. He cut out the two pieces of wood with the print on and, using a stamp pad and ink, took Francisca’s fingerprints for comparison. He sent both back to La Plata for analysis.

The first fingerprint database

In 1892, the police department in La Plata, Argentina held the very first working fingerprint database in the world. This had been created, a year earlier, by Juan (also known as ‘Ivan’) Vucetich. Originally from Croatia, Vucetich had emigrated to Argentina in 1882. A skilled mathematician, he found employment with the police in La Plata, first in accounting and then statistics. In 1891, Chief of Police Guillermo Nunes instructed Vucetich to set up an anthropology office, following the groundbreaking work of French criminologist Alphonse Bertillon.

In the 1880s, Bertillon had developed an anthropometric system to measure the body of suspected habitual offenders. Based on the assumption that the dimensions of no two adult bodies are exactly the same, and do not change throughout life, he designated eleven anatomical parts to be measured, from which he compiled individual profiles. (I’ll examine this in more detail in a later post.)

Juan Vucetich, 1858-1925

Vucetich carried out his superior’s orders but soon became interested in the new science of fingerprinting as a means of identification, after reading an article in a scientific journal by Francis Galton. He decided to experiment for himself and, using mummies from La Plata Museum and corpses from the local morgue, Vucetich simplified Galton’s system and developed his own practical classification based on four fingerprint types. His first trial was with 23 known offenders, whose prints he collected. This is believed to be the first time that fingerprints were used for a police database. By the end of 1892, Vucetich had compiled the prints of 1,462 individuals. But, would this prove Ramón Velásquez’s innocence?

A scientific breakthrough

When Juan Vucetich compared the fingerprints found at the scene of the double murder with those of Francisca Rojas, they were a match. Confronted with the evidence, she confessed to the murder of her two children, claiming that it had been a murder-suicide attempt, following her abusive husband’s threats to take them away from her.

On 20 September 1894, Francisca Rojas was convicted of murder and imprisoned for life. In 1902, fingerprinting was adopted officially in Argentina, as the sole means of identification in criminal investigations. The Fingerprint Bureau in Scotland Yard had been established the year before, and New York followed suit in 1903.

Fingerprinting pioneer Juan Vucetich became director of the Center for Dactyloscopy in Buenos Aires and published two books on his techniques. He died of tuberculosis in 1925. The provincial police academy near La Plata still bears his name, as well as the Police Center for Forensic Examinations in Zagreb, Croatia. He is remembered by a memorial in his home town of Hvar.

In my next post for paid subscribers, I will be sharing a brief history of fingerprinting.