First Murder Solved by a Fingerprint

First Murder Solved by a Fingerprint

In 1892, a double murder of two children in Argentina was the first ever successful conviction for homicide using fingerprinting. 

On 29 June 1892, in the suburbs of Neocochea, a coastal city in the southeast of Argentina in the province of Buenos Aires, Ponciano Caraballo and his neighbour Ramón Velázquez came upon a terrible scene in the bedroom of the Caraballo family home. Lying on the bed were Caraballo’s two children, Ponciano Ernesto, aged 6 and Feliza, 4, and their mother Francisca Rojas. Their throats had been slit. The siblings were dead, but Ponciano’s wife was still breathing. Although she had lost a lot of blood, her injuries were quite superficial, and she was soon able to reveal what had happened.

Francisca, who had been married to Ponciano for four years, told the police that she and her children had been attacked by their neighbour, agricultural labourer Ramón Velázquez. He had tried to seduce her and when she’d refused, he had threatened to kill them all. She later changed her testimony and stated that Velázquez had been attempting to take her children away from her, on behalf of her husband, from whom she was estranged. Whatever the reason for the attack, Ramón Velázquez was arrested on suspicion of murder.

As was customary at the time, the police used torture to elicit a confession from the accused. Velázquez was subjected to several brutal beatings, and forced to spend a night locked in with the children’s bodies. It is also alleged that a police officer dressed up as a ghost one night to scare the prisoner into confessing. Despite the violent and intimidating interrogations, Velázquez 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.


As soon as Inspector Álvarez examined the crime scene, his suspicions were aroused. Firstly, the bedroom door was barred from the inside with a shovel, suggesting that the killer had not left the room by the door. Francisca claimed that Velázquez had struck her with the shovel, but there were no marks on her body. The murder weapon was a kitchen knife and the inspector surmised that a labourer would be more likely to have used the knife that he carried on his belt rather than go to the trouble of finding a domestic one. Álvarez found a soiled rag in some shrubs by the well outside which he thought had been used by the perpetrator to wipe their hands.


Rojas’ right thumb print


The key piece of evidence, however, was a brown mark on the bedroom window, which turned out to be a bloody fingerprint and which the inspector thought looked like the print from a woman’s hand. He cut out two pieces of wood with the print on and, using a stamp pad and ink, took Francisca’s fingerprints. He sent everything to La Plata for analysis.


In 1892, the police department in La Plata, Argentina had the very first working fingerprint database in the world. This had been created, a year earlier, by Juan Vucetich. Originally from Croatia, Vucetich had emigrated to Argentina in 1882. A skilled mathematician, he found employment with the police in La Plata, working on 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. 


Juan Vucetich (1858-1923)


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 by Francis Galton. He decided to experiment and, using mummies from La Plata Museum and corpses from the local morgue, he 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 revolutionary method of identification prove Ramón Velázquez’s innocence?


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 Ponciano and Feliza away. 

On 20 September 1894, Francisca Rojas was convicted of murder and imprisoned indefinitely. 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 1923. Almost a century later, the police academy near La Plata bears his name, as well as the Forensic Science Centre in Zagreb, Croatia. He is remembered by a memorial in his home town of Hvar.






Catching the Killers: A History of Crime Detection, James Morton (Ebury Press, 2001) 

A Forensic Forum, Robin Odell (Mango Books, 2017)

El felicidio de Francisca Rojas que dio inicio a la dactiloscopia, El Patagónico, 30 October 2016

El caso de Francisca Rojas, Clarín, 8 July 2016

Francisca Rojas blog 


Featured image – fingerprint card, Francisca Rojas © Direction Museo Political-Ministerio de Seguridad de la Provincia de Buenos Aires, Argentina

Vucetich memorial © Hhgygy (Wikicommons)




  1. Vucetich must be the only fingerprint analysis who has been immortalised by a statue.

    • I think that must be the case – a good point, thank you!


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