Francisco Xavier Arce Montes was born on 14 March 1950 in Spain. He grew up as the only son of middle-class parents who owned a small grocery store. Montes later told investigators that his childhood was deeply unhappy, a claim often cited in psychological evaluations during his trials. From an early age, he exhibited signs of obsessive-compulsive behavior — most notably an extreme concern with cleanliness. As a teenager, he reportedly avoided touching public objects without a barrier, often using a handkerchief to operate doorknobs or light switches.

His psychological struggles escalated in early adulthood. At age 20, Montes was arrested after exposing himself to a female neighbor. A psychiatric assessment following the incident diagnosed him with depression and what was described at the time as “progressive schizophrenia.” This diagnosis, however, did not prevent him from continuing to escalate his predatory behavior in the years that followed.

By the early 1980s, Montes’ deviant impulses had become criminal. His offenses, primarily targeting girls aged 11 to 13, spanned multiple countries. His first known attack took place in 1981 in the Netherlands, where he broke into a youth hostel room and sexually assaulted a girl. The victim, who was able to identify him years later, testified against him during his murder trial decades later. Montes was later imprisoned in Germany during the mid-1980s for an armed rape, but upon release, he continued traveling across Europe and committing similar crimes in Spain, France, and the Netherlands.

Despite repeated incarcerations, Montes’ behavior became increasingly bold and violent, culminating in the murder that would make him one of Europe’s most notorious serial offenders. 

On the night of 18 July 1996, Francisco Xavier Arce Montes committed his most heinous crime: the sexual assault and murder of Caroline Dickinson, a 13-year-old British schoolgirl visiting France on a class trip. Dickinson and her classmates were staying in a youth hostel in Pleine-Fougères, Brittany, when Montes slipped into their shared room. Without waking the other girls, he assaulted and suffocated Caroline as she slept. She was discovered dead the following morning.

Investigators quickly suspected a serial predator. They linked the assault to an attempted attack just days earlier at a hostel in Saint-Lunaire, where a man had entered a girls’ room but fled when a victim awoke. Police inquiries revealed that a Spanish man named Francisco Montes had frequently stayed in hostels near the sites of these incidents. However, by the time authorities identified him as a suspect, Montes had fled Europe for the United States.

The case remained unsolved for five years until Tommy Ontko, a U.S. immigration officer, stumbled upon a British newspaper article marking the anniversary of the Dickinson case. Curious, Ontko checked immigration records and discovered that a “Francisco Arce-Montes” had entered the U.S. and was currently in custody in Miami Beach, Florida.

Montes had been arrested there for a lewd and lascivious assault on a young Irish tourist in a youth hostel — a crime mirroring his European assaults. Sergeant Angel Vazquez of the Miami Beach Police Department collected DNA samples from Montes, which matched genetic material recovered from both the Miami attack and the Dickinson murder. Vazquez also connected Montes to four additional sexual assaults committed in Miami.

With the DNA evidence linking him directly to Dickinson’s murder, the State of Florida suspended its charges so that Montes could be extradited to France. His trial in 2004 relied heavily on forensic evidence. A court-appointed psychologist described him as displaying a “clear male pedophilic attitude.” Adding to the gravity of the case, Montes’ mother submitted a statement disowning her son, declaring that she would rather live on the streets than share a home with him.

On 14 June 2004, Montes was convicted of the rape and murder of Caroline Dickinson and sentenced to 30 years in prison. An appeals court upheld the conviction in 2005, and Montes subsequently abandoned further appeals. He remains incarcerated, and no additional trials for his other crimes have been reported publicly.