Michel Paul Fourniret was born on April 4, 1942, in Sedan, France. He was the son of a metal worker and a homemaker. As a child, Fourniret was described by his acquaintances as quiet and intelligent. He had interests in chess and classical music. Later in his life, he claimed that he had been sexually abused by his mother during his childhood.

As he grew up, Fourniret drifted through various menial jobs. His work experience included being a forestry worker and a school supervisor. His life took a significant turn when he was first arrested in 1966 for sexually assaulting a young girl.

After this initial arrest, he was imprisoned again in 1984 for sexually assaulting another five young girls. While in prison, he began corresponding with Monique Olivier through a pen pal program. In his letters, he shared his violent fantasies of raping and murdering young girls. Monique responded by saying she would help him fulfill these fantasies if he killed her husband, which he did not do.

Fourniret was released from prison in 1987. After his release, he began a relationship with Monique Olivier. They later became a criminal duo, involved in a series of serious crimes.

On 11 December 1987, Michel Fourniret and his accomplice, Monique Olivier, targeted 17-year-old Isabelle Laville in Auxerre. They lured her into their car under the pretense of needing directions. After gaining her trust, they reached a spot where Fourniret waited. He choked Isabelle with a rope while Olivier sedated her. They took her to their home, where Fourniret raped and strangled her. Eventually, they disposed of her body in a disused well in Bussy-en-Othe. Her remains were not discovered until 2006.

In March 1988, Fourniret and Olivier killed 30-year-old Farida Hammiche. They had previously helped her recover stolen gold. On 12 April, they lured Hammiche out of her home, took her to a nearby forest, and strangled her. They buried her body and stole the gold, using the money to buy a château in Donchery. Hammiche's remains were never found.

On 3 August 1988, they spotted 20-year-old Fabienne Leroy in a supermarket parking lot. With Olivier pretending to be ill, they convinced Leroy to assist them. They drove her to a forest, where Fourniret raped her and then shot her in the chest. Her body was found the next day.

In January 1989, 21-year-old Jeanne-Marie Desramault met Fourniret on a train. They later invited her to their home, where Fourniret asked if she was a virgin. After she revealed she had a boyfriend, he attacked her and ultimately strangled her. They buried her body in the garden of their château.

On 20 December 1989, they kidnapped 12-year-old Elisabeth Brichet from Saint-Servais. After driving her back, Fourniret strangled her at the château and buried her near Desramault's body. Elisabeth was missing for many years until her remains were found in 2004.

On 21 November 1990, the couple kidnapped 13-year-old Natacha Danais after leaving a court session. They lured her to a secluded area, where Fourniret stabbed and strangled her. Her body was discarded on the beach.

In 2000, Fourniret committed two more murders. He lured 18-year-old Céline Saison into his van, raped her, and strangled her, leaving her body in a forest. Her remains were found later that year. In May 2001, he invited 13-year-old Mananya Thumpong to his home, later strangling her as well. Her remains were discovered in 2002.

Fourniret was arrested in June 2003 after a failed kidnapping attempt. He confessed to killing multiple women, and Olivier later implicated him in the murders. They were extradited to France, where they helped find the bodies of some victims. In 2008, Fourniret was convicted of several murders and sentenced to life in prison. He continued to admit additional murders until his death in 2021.