A serial killer allegedly admitted to using a ligature to attack his cellmate before his death at a B.C. jail last November, according to details contained in a search warrant obtained by CBC.

The documents were filed by RCMP officers investigating the death of inmate Jeremy Phillips at Mountain Institution in the Fraser Valley last November.

Phillips, 33 was found dead in the cell he shared with Michael Wayne McGray, a man serving six concurrent life sentences for murders committed in the Newfoundland and Nova Scotia.

According to the documents, as prison officials rushed to the cell when an emergency button was activated, the convicted serial killer McGray stood by the door.

"I tried to wake my roommate up for 20 minutes. You should get in here and check him out," he said, according to the documents.

Jeremy Phillips was dead, blood around his nose, mouth and pillow.

A short while later, while he was being escorted to a holding cell, McGray allegedly told a corrections manager he assaulted Phillps with a ligature made from a bed sheet and then flushed it down the toilet, according to the documents.

McGray said the incident took place minutes after a 10:15 p.m. PT head count. But officers didn't find the body for another 12 hours.

Police later seized an item described as possibly being a bed sheet from Mountain Institution's pump station. Investigators also found a post that appeared to match marks on Phillips face.

No charges have been laid in Phillips' death. But after reviewing the results of an autopsy, police said it is clear Phillips was the victim of a homicide.

The Moncton, N.B. man was serving time for aggravated assault and had reportedly asked to be moved from the cell he shared with McGray because of his concerns for his safety.

Serial killer had urge to kill

A decade earlier McGray told the media he'd killed 16 people, although he was only convicted in six cases. In a CBC News interview, he talked about his urge to kill, and what he would do, even inside a prison.

"It's like a craving or hunger... It's something I have to do... It gets to a point where I just can't control it anymore," he said.

"I want to go to an institution, a hospital somewhere for a while where I can get some treatment because if I don't, just because I'm in prison doesn't mean the killing's going to stop," he said.