In 1858, Argentine police officer and scientist Juan Vucetich was born in present-day Croatia (then part of the Habsburg empire). He came to Buenos Aires in 1884. He was apparently a music, languages, and mathematics prodigy.
In 1888, he joined the provincial police in La Plata, where he studied anthropometry, but soon became convinced that anthropometry was flawed, resulting in mistaken identities and the imprisonment of innocent people. He turned his attention to the budding science of fingerprinting.
Vucetich developed a method of classifying fingerprints into four different types, a system that is still the basis for the one used in Argentina today. The biggest test of his fingerprinting system came in 1892, when it was used to resolve a murder, a first in the history of criminology.
On June 29, 1892, in the city of Necochea, Francisca Rojas killed her six- and four-year-old children by slitting their throats. She then superficially stabbed herself and said she was also a victim of the attack. She accused neighbor Ramón Velázquez. She apparently did so because she blamed Velázquez for telling her husband of her infidelity. Velázquez denied having killed the children.
Buenos Aires provincial police chief Guillermo J. Nuñes sent police officer Eduardo M. Álvarez, a colleague of Vucetich and well-versed in his fingerprinting techniques, to investigate the crime. At the crime scene, Álvarez found a bloody fingerprint on the door and showed that it came from the mother and not from Velazquez. Rojas was tried and convicted.
Vucetich’s methods attracted great attention throughout the field of criminology and his system quickly spread. Fingerprinting had arrived and it soon became the preferred method for individual identification.