A convicted serial killer who methodically strangled a fellow inmate to death in their shared cell has placed blame on the federal corrections system for transferring him out of a higher-security prison.

During a police interview played at a coroner's inquest Monday, Michael McGray, 45, described in vivid detail how he planned and then killed 33-year-old Jeremy Phillips in an Agassiz, B.C., prison in November 2010 as part of a fake hostage-taking scenario.

"I don't know why they made the mistake of putting me here. I'm not a 'medium' inmate," McGray told a pair of homicide investigators the day after the crime.

'I had a hiatus for 15 years and I just couldn't hold back any more.'—Michael McGray on his impulse to kill Jeremy Phillips

"We didn't have a beef ... This was all about me, it wasn't about him."

McGray was a six-time convicted serial killer from Eastern Canada who initially was held in a super-maximum security prison in Quebec. He was later transferred to the Kent high-security prison in B.C., and then just before the murder, was moved to Mountain Institution, which is classified as medium-security.

The inquest was called because B.C.'s chief coroner wanted the "issues raised surrounding the safety of inmates in the prison system" to be explored.

The jury of three men and two women is tasked with making recommendations to prevent similar deaths in the future.

McGray pleaded guilty to first-degree murder a year after he killed Phillips and was given another life sentence. Phillips had been serving time for aggravated assault.

In the interview, McGray expressed resignation to the homicide investigators, noting he hadn't killed anyone in years.

"It's a mental health issue," he said. "I had a hiatus for 15 years and I just couldn't hold back any more."

'I'm a serial killer'

McGray went on to eagerly outline the steps he took to gain the trust of his new, junior cellmate as though he were telling a story.

"I'm a sociopath, I'm a serial killer," said the large, muscular man, repeatedly telling the officers it's only a matter of time until he kills again.

"I've never been offered any help," he added. "I've never been able to address it, it's an endless, vicious cycle."

The plot to release his pent-up urges flashed into his head after he had bunked with Phillips for only a few days, McGray said. The younger man had been dreaming up scenarios to be sent to the hospital's medical infirmary, and he proposed the notorious killer tie him up with bedsheets.

He tightly bound and gagged the willing man, then strangled him for about five minutes, he said. He punched him once in the head, he said, to check to see if his victim was dead.

No guards, located not far from their closed-door cell, came to investigate.

McGray said he flushed some evidence and lay next to the body, which he had covered to make it appear the man was sleeping, for the rest of the night.

The killer said he finally pushed a panic button in the cell to alert prison staff the man was dead, at first telling them he found Phillips that way after the night.

The inquest also heard from the Corrections officer within Mountain Institution who made the decision to pair McGray and Phillips as cellmates.

Richard Woods, who had been on the job about 1.5 years at the time, said his role was to ensure compatibility.

"I never saw any kind of behaviour I was concerned about," Woods said of McGray, noting he had read the man's profile.

A pathologist who conducted the autopsy told the inquest his findings were not conclusive.

He found minor bruising on the face and a mark on Phillips' neck, but did not find any "truly major trauma" or evidence natural disease or drugs killed the man.