Karla Leanne Homolka was born in Port Credit, Ontario, on May 4, 1970, into a comfortable suburban family, and met Paul Bernardo in 1987 when she was seventeen. She worked at a veterinary clinic in St Catharines, which is where the anaesthetic came from.
At Christmas 1990 she drugged her fifteen-year-old sister Tammy with halothane stolen from the clinic and animal tranquillisers put in her drink, so that Bernardo could rape her. Tammy vomited and choked and died. It was recorded as an accident.
In June 1991 they abducted fourteen-year-old Leslie Mahaffy, held her at their house in Port Dalhousie, raped her over two days and killed her, and Bernardo encased the body in concrete and put it in Lake Gibson. In April 1992 they took fifteen-year-old Kristen French from a church car park in St Catharines and did the same over the Easter weekend. Both girls were filmed.
In February 1993 Homolka went to the police after Bernardo beat her badly with a torch, and her lawyers negotiated. She was presented as a battered woman coerced by a violent husband, and in May 1993 she pleaded guilty to two counts of manslaughter for twelve years, in exchange for testifying against him. The videotapes, hidden in a light fitting at the house, were not recovered until after the deal was signed. When they were played at Bernardo's trial in 1995 they showed her as an active and willing participant, and in one of them assaulting a fourth girl on her own.
The agreement became known across Canada as the deal with the devil, and it produced a formal judicial review, the Campbell inquiry, into how the police and prosecution had handled it. A publication ban on the details was imposed and widely defied.
She served her full sentence and was released in July 2005 without parole. She has lived since in Quebec and the Caribbean under other names, remarried, and has three children. Her presence has repeatedly become a news story, most recently when it emerged that she had been volunteering at her children's school. She has never given an account that matches the tapes.