Days after Mark McCreadie was found dead in Victoria Park in April 2014, police got a call from someone claiming to have information that might have something to do with his death.

The man placing the call was Derrick Lawlor. At the time, he was staying in the psychiatric ward at Grand River Hospital.

In time, Lawlor would come to be charged with assaulting McCreadie. That charge was later upgraded to murder.

He has pleaded not guilty. On Thursday, his trial heard from the Waterloo Regional Police detective tasked with investigating the case.

Det. Const. Les Pyke told jurors that after calling police, Lawlor agreed to take part in a recorded interview. During that interview, Lawlor said he had been raped by a man the previous year, and was looking to get revenge by targeting “sexually deviant” men.

“I call it cruising for perpetrators,” he said.

Lawlor told police that when he was with another man, he would find himself with an urge to hurt that man.

“I always wanted to kill them,” he said. “Everything rages in me.”

Lawlor also told police what he could remember from the night before McCreadie’s body was found.

He said he drank beer on his own in Victoria Park, and remembered nothing else until waking up at Grand River Hospital the next morning. Such blackouts were not uncommon for him, he said.

He later recalled a few memories from those missing hours – including being involved in a sexual three-way with two other men, having a scarf with him, choking, and noticing blood on his hands.

"If I'm responsible in any way, I want to take responsibility for it," he said.

The Crown alleges that McCreadie was killed by a scarf or some similar soft ligature. His cause of death was ruled to be strangulation.

Surveillance video shown to jurors on Thursday places Lawlor at various locations between Victoria Park and Grand River Hospital during the hours he can’t account for.