A man was convicted of slowly strangling 11 prostitutes as he raped them during an eight-month killing spree.

Benjamin Atkins, 25, faces mandatory life imprisonment after his conviction Thursday. He had pleaded innocent by reason of insanity, and his lawyer blamed the slayings on Atkins' addiction to crack cocaine and a horrible childhood.The victims were prostitutes whom Atkins lured into abandoned buildings along a decrepit Detroit street with promises of crack, police said.

Two juries jointly heard the case. One was from Detroit, where three of the slayings occurred, and the other from the Detroit enclave of Highland Park, where the other eight took place. The juries could issue verdicts only for the murders in their community.

"He was a very diabolical killer, and I think he's going to get exactly what he deserves," one of the jurors said afterward. The jurors were not identified.

Defense Attorney Jeffrey Edison said Atkins was abandoned by his mother at age 2 and was raped by his caseworker beginning about age 10 at a boys' home in Detroit. Edison said Atkins had watched his mother, a prostitute, turning tricks in a car.

Prosecutors relied heavily on an 87-page confession Atkins gave to police after survivor Darlene Saunders led them to Atkins.

"It's not all women I hate, it's the prostitutes," Atkins told police in the confession. "This is what they want."