Alegre was born in 1968 in Toulouse. He was a serial rapist from his late teens, with a long record of assaults, and between 1989 and 1997 he killed five women: Valerie Tarriote, twenty-two; Laure Martinet, nineteen; Martine Matias, twenty-nine; Mireille Normand, thirty-six; and Isabelle Chicherie, thirty-one. All were raped and strangled.
He was arrested on September 5, 1997 and sentenced to life imprisonment on February 21, 2002, with a twenty-two-year minimum.
What followed is the reason the case is well known in France. From 2002, in interviews with an investigating judge and with police, he claimed to have taken part in sadistic parties involving judges, senior officials and a politician in Toulouse, and to know of further murders connected to them. The claims were pursued for two years, and a magistrate and police officers were suspended and reputations destroyed. In 2005 a judicial inquiry concluded that the allegations were fabricated. Two of the investigators who had promoted them were disciplined, and one of the officers involved was later convicted in connection with the affair.
Alegre was subsequently convicted of further rapes in separate proceedings. The five murders are firm; the additional deaths he claimed were not established, and the higher figure reflects claims rather than evidence. The case is cited in France on the credibility of confessions offered by convicted prisoners with something to gain.