MONTREAL (AP) — Convicted Canadian serial killer Robert Pickton, who brought female victims to his pig farm during a crime spree near Vancouver in the 1990s and early 2000s, was assaulted in prison and has been hospitalized in life-threatening condition, authorities said Tuesday.

A 51-year-old inmate was in custody for the assault Sunday at a prison in Quebec, police spokesman Hugues Beaulieu said.

The 74-year-old Pickton was convicted of six counts of second-degree murder and sentenced to life in prison in 2007, with the maximum parole ineligibility period of 25 years, after being charged with the murders of 26 women.

Police began searching the Pickton farm in the Vancouver suburb of Port Coquitlam more than 22 years ago in what would be a years-long investigation into the disappearances of dozens of women.

The remains or DNA of 33 women, many picked up from Vancouver’s Downtown Eastside, were found on Pickton’s pig farm in Port Coquitlam, British Columbia. He once bragged to an undercover police officer that he killed a total of 49 women.