The verdict means Richard Kachkar, 64, who had been charged with first-degree murder, will spend his time in a psychiatric facility instead of prison.
A panel of experts will review his mental state annually to decide whether he can be released. This is a process in which the victim's families take part — and can be a constant reminder of the trauma they experienced.
The slain officer's widow, Christine Russell, said the verdict left her with "no closure."
"In a verdict of not criminally responsible, my family, most likely myself, will have to fight this for the rest of my life," she told reporters Wednesday.
Bill would impose restrictions on mentally ill offenders
Russell said she would push for Bill C-54, introduced by the Tories last month, which would include stringent restrictions for those found not criminally responsible due to a mental disorder.
The proposed legislation is in response to cases such as Vince Li, who beheaded Tim McLean, 22, on a GreyHound bus in 2009, but was granted a day pass from hospital three years later.
The bill would make changes to the Criminal Code to protect the public from an accused person designated as "high-risk non-criminally responsible."
Instead of a review board, only courts could release offenders with this designation. They would not receive unescorted day passes, and mental-health reviews would take place every three years instead of annually. It would also ensure that victims would be notified when an individual with this designation is discharged.
"We are giving the courts the powers they need to keep those deemed too dangerous to release where they should be — in custody," Prime Minister Stephen Harper said in February after the bill was tabled in Parliament.
Lawyer calls bill unconstitutional
However, lawyer Anita Szigeti called the legislation unconstitutional and says non-criminally responsible verdicts are extremely rare.
Statistics show a person released from the mental-health system is much less likely to reoffend than someone leaving the prison system, she said.
"It's a bit of blood thirst," she told CBC News. "People want an eye for an eye, they want parity and equality and some sort of measures taken."
Increasing funding to help the mentally ill is a better solution, Szigeti said.
However, Carol de Delley, McLean's mother, has said her son's killer should never be released from the Manitoba mental health centre where he has been committed.
"The fact is that he could do it again," she told CBC News last year. "If he did, who would be ultimately responsible then?"