OTTAWA -- Veterans Affairs Minister Seamus O'Regan says he's looking at why his department decided to fund PTSD treatment for a convicted killer.

Christopher Garnier was convicted last year of killing an off-duty police officer from Truro, N.S. He was found guilty of second degree murder and interfering with a dead body after strangling Catherine Campbell and putting her body in a compost bin in September, 2015.

Garnier is receiving treatment for his PTSD through Veterans Affairs Canada because his father is a veteran.

O'Regan said he thinks his reaction to the news was the same as many other Canadians.

"How could this happen? So I will be looking into how and why this particular decision was made," O'Regan told CTV News.

The federal minister said privacy prevents him from discussing the case, but said the policy at Veterans Affairs is to provide treatment for the whole family when a veteran has PTSD.

"There are cases too where treatment for family members can help that veteran with their PTSD," he said.

"But again I have to say, we will be looking into how and why in this particular situation this decision was made."

Campbell's aunt said on Facebook that veterans should be outraged about the treatment.

Jim Davis, whose son Paul was killed in Afghanistan in 2006, said he's horrified that Veterans Affairs is paying for Garnier's treatment.

"VAC owes him no responsibility. If [Correctional Services Canada] want to help him, that's up to them. But not VAC," Davis told CTV News.

The Canadian Press reported Tuesday that Garnier's lawyer told the Nova Scotia Supreme Court earlier this month that Garnier's crime brought on the mental illness.

Earlier Wednesday, Conservative critics called on O'Regan to step in, labelling it "an absolute travesty," the Canadian Press reported.

O'Regan said 96 per cent of people who seek therapy for PTSD through Veterans Affairs are approved, and the four per cent who aren't approved are usually either not veterans or don't have PTSD. He said treatment begins before people are approved, and that there may be a wait for access to a psychiatrist, but that the department does its best to make sure medical care is provided as soon as possible.

The minister said the department is "looking into it immediately" but he doesn't know how long the investigation will take.