Francesca Rojas: The First Murderer to be Apprehended by Fingerprint Evidence

Apr 30, 2024 3 comments

On June 29, 1892, in the town of Necochea, located in the southeast of Argentina in the province of Buenos Aires, two young children were discovered brutally murdered in their home. The victims were six-year-old Ponciano Carballo Rojas and his four-year-old sister, Feliza. Their throats had been slit. Their mother, Francesca Rojas, also sustained a knife injury to her neck, although her wounds were superficial, and Francesca apparently survived the attack.

Francesca initially claimed that their neighbor, Ramón Velázquez, was responsible for the attack, alleging that he killed her children because she had rejected his advances. Later, she changed her testimony, asserting that Velázquez had been attempting to take her children away from her on her husband’s instructions, as he was planning to leave her. Whatever the truth may be, Ramón Velázquez was arrested on suspicion of murder.

Fingerprints of Francesca Rojas. Photo credit: National Library of Medicine

Velázquez was interrogated by the police and even subjected to torture, but he vehemently denied killing the children. According to one version of the story, Velázquez was forced to spend a night locked in a cell with the children’s bodies in an effort to extract a confession. However, Velázquez maintained his innocence and stuck to his story that he had been out with his friends at the time of the murders. He even had an alibi who corroborated his account.

Faced with a dead end, the local police requested assistance from the force in the provincial capital, La Plata, and Inspector Eduardo Álvarez was dispatched to Necochea to conduct further investigation.

Upon examining the crime scene, which was now several days old, Álvarez discovered a bloody fingerprint on the doorway of the children’s bedroom where the massacre took place. He had the piece of wood with the fingerprint removed. He also obtained the fingerprints of Velázquez and Francesca using ink on paper and sent these along with the piece of wood to La Plata for examination.

At that time, the use of fingerprints for crime detection was in its nascent stage. Instead, fingerprints were primarily employed for identification purposes. In ancient China, around 220 BC, fingerprints were utilized to authenticate government documents. These documents, typically composed of bamboo slips or pages, were rolled and bound with string, sealed with clay. On one side of the seal, the name of the author would be impressed, usually in the form of a stamp, while on the other side, the author's fingerprint would be impressed. With the invention of paper in the 2nd century, signing documents with fingerprints became a common practice in China, later spreading to India.

European academics began to seriously study fingerprints from the late 16th century onwards. In 1686, Marcello Malpighi, a professor of anatomy at the University of Bologna, identified ridges, spirals, and loops in fingerprints. Then, in 1788, Johann Christoph Andreas Mayer, a German anatomist, became the first European to conclude that fingerprints were unique to each individual.

By 1892, the police department in La Plata, Argentina, had the very first working fingerprint database in the world, established by anthropologist and mathematician Juan Vucetich. Originally from Croatia, Vucetich was employed as a statistician with the Central Police Department in La Plata until his promotion to the head of the bureau of Anthropometric Identification. Inspired by the ideas of Francis Galton, Vucetich began experimenting with fingerprints in 1891. He began recording the fingerprints of criminals and developed his own classification system. Vucetich’s classification system and the individualization of prisoners through the use of fingerprints marked the first practical applications of fingerprint science by law enforcement personnel.

When analysts trained by Vucetich analyzed the fingerprint samples sent by Inspector Eduardo Álvarez from La Plata, they found that the fingerprint on the doorframe matched that of Francesca Rojas. Confronted with this evidence, Francesca confessed to the murder of her two children and admitted to faking her own injuries in an attempt to improve her chances of marrying her boyfriend, who was known to dislike children. Francesca was subsequently convicted and sentenced to life imprisonment.

The Rojas murder case is considered to be the first homicide solved by fingerprint evidence. The case vindicated  Vucetich's faith in fingerprints, and in 1903, Argentina became the first country to rely solely on fingerprints as a method of identification. The Rojas case also inspired other nations to adopt dactyloscopy in forensic investigation leading to a flurry of convictions that wouldn’t have been possible without fingerprint evidence.

One of the earliest such cases occurred in 1898 in the district of Jalpaiguri in West Bengal, India. The manager of a tea garden was discovered lying on his bed with his throat cut, and his dispatch box and safe were emptied of several hundred rupees. Initially, suspicion fell upon one of the coolies employed on the garden, as the deceased had the reputation of being a harsh taskmaster, or perhaps his cook, whose clothes bore some blood spots, might be the culprit. There was also suspicion against the relatives of a woman with whom the murdered man had a liaison. Additionally, a wandering gang of Kabulis with criminal tendencies, who had recently encamped in the vicinity, was considered suspect. Moreover, an ex-servant whom he had caused to be imprisoned for theft was under suspicion. However, police inquiries satisfied them that there was insufficient evidence to incriminate the coolies, the woman's relatives, or the Kabulis. The ex-servant had been released from jail several weeks prior, and there were no reports of his presence in the district since then. Some blood stains were found on the cook, but these were explained as coming from a pigeon he had killed for his master’s dinner, supported by chemical analysis.

Inside the dispatch box, police discovered a diary with two very faint brown smudges on the outside cover. Upon closer examination with a magnifying glass, these smudges were revealed to be fingerprints. The Bengal Police maintained a database of fingerprints of all persons convicted of certain offenses, and when the impression on the diary was compared, it matched those of the ex-servant. Consequently, he was arrested and brought to Calcutta for trial. However, he was convicted only of theft, as there was a lack of corroborating evidence for murder.

The idea of using fingerprints to apprehend criminals eventually made its way into fiction as well. In Mark Twain’s novel Pudd'nhead Wilson, published in 1893, a courtroom drama unfolds where a murder mystery is resolved through fingerprint identification. Similarly, in the 1903 short story The Norwood Builder by Sir Arthur Conan Doyle, the renowned sleuth Sherlock Holmes solves a murder and exposes the culprit using a bloody fingerprint.

The development and utilization of fingerprinting as a tool for criminal investigation have revolutionized law enforcement practices worldwide. From its early beginnings as a method of identification to its pivotal role in solving crimes depicted in literature, fingerprinting continues to be a cornerstone of forensic science.

Correction: In an earlier version of the article an image of Ethel Rosenberg was incorrectly labeled as belonging to Francesca Rojas

# Jeffrey G. Barnes, The fingerprint sourcebook


  1. Come on. That photo is Julius and Ether Rosenberg, executed spies in the USA.

  2. The picture above of Francesca Rojas in police custody is in fact Ethel Rosenberg and her husband Julius who were convicted of spying for the Soviet Union,

  3. The picture above is not Francesca Rojas. It is Ethel Rosenberg and her husband Julius who were convicted and executed for spying for the Soviet Union in the early 1950's.


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