A union representing prison officers is raising concerns about changes to segregation in Canadian prisons after five inmate homicides at Stony Mountain Institution in 16 months.

Five people have been killed while in custody at the prison since January 2018, including two people so far this month. The men were killed while serving time for charges including murder, assault and robbery.

On Monday, Adrian Fillion, 42, died in hospital after he was found unresponsive while in custody. His death came eight days after another man, Michael Monney, 27, was fatally stabbed while in custody at the prison.

The other three prisoners killed at Stony Mountain Institution since January 2018 are Nolan Randall Thomas, Adam Kent Monias and Max Maurice Richard.

James Bloomfield, president of the Prairies region for the Union of Canadian Correctional Officers, believes the deaths are the result of multiple factors, including gangs and drugs in institutions.

He also points to changes in how federal prisons use segregation, following Ontario and B.C. court decisions in December 2017 and January 2018 that found aspects of its use unconstitutional.

Since that change, he says, prison officers haven't had enough direction on how to manage populations, contributing to increased violence.

"In a lot of these cases, these things are burned into your memories so, so badly that, I mean, it's stuff that you don't forget for the rest of your life," Bloomfield said.

"It really is hugely impacting on staff, and not only the families who lost people."

A spokesperson for the Correctional Services Canada said in an email the agency doesn't tolerate violence in any of its institutions, and continues to work to ensure safety. Measures include enhancing intelligence and information systems, implementing population management and mental health strategies and adding new search and surveillance technology.

She said the agency acknowledges the challenges associated with working in corrections, and has multiple strategies in place to manage and reduce violent incidents.

She said a new government bill that will eliminate segregation will also implement structured intervention units, a separation measure that will work on pro-social skills with inmates.

"CSC recognizes the need for the separation of inmates who cannot be maintained in a mainstream inmate population for security or other reasons, and seeks to integrate evolving best practices into its policy development," she wrote.

Research needed

However, a University of Winnipeg professor says after 16 months, it's too early to say whether the changes following the B.C. court's decision have led to more violence.

Michael Weinrath, a professor of criminal justice, says he would want to see real research over a longer time period before making that assessment.

Adrian Fillion, who died on Monday, is the fifth inmate killed at Stony Mountain Institution since January 2018. (Kelly Malone/CBC)

Statistically rare events such as homicides can have random or episodic fluctuations from year to year, he says. In prisons, they're influenced by a variety of factors, and tend to reflect patterns in the population outside the institution.

As well, he adds, Canada needed to change the way its prisons use segregation, which can be debilitating for prisoners.

"You can have violence as a result of segregation. You can have mental health problems. You can have suicide attempts. It was time for Corrections [Canada] to address this, and it was time for corrections to to address this. And I can understand that there would be a difficult and challenging adjustment period," he said.

"Even though there may be some tweaks that may be needed — and we may have to do research to examine that and find out what those issues are — I see the move away from punitive segregation solitary confinement … as a positive one."

Prisoner rights group concerned

John Hutton, head of the John Howard Society of Manitoba, says he can't speak to whether violence at Stony Mountain was connected to changes in segregation. But he says he hopes the federal prison ombudsman looks into the issue.

"We're very concerned about the incidents over the last year and a half, and we hope that the Office of the Correctional Investigator is able to look into what's been happening," he said.

Prior to the courts' rulings, efforts to limit solitary confinement had been underway in Canada for roughly three years.

Correctional investigator Ivan Zinger urged caution about changes to solitary confinement in September 2017. At the time, he said, the reduction in solitary confinement was leading to more violence in prisons across the country.

"It hasn't happened as smoothly as everybody thought," he said. "After crunching the data … it's clear to me now that it has had unintended consequences on the safety and security of inmates."