A man who killed a Toronto police officer with a snow plow has been found not criminally responsible.

The verdict means the jury believed 46-year old Richard Kachkar couldn’t appreciate what he was doing when he hit and killed 35-year-old Sgt. Ryan Russell because Kachkar was mentally ill.

The judge had told the jury there was “no doubt” Kachkar was driving the stolen snow plow on Jan. 12, 2011, but what the jury had to consider was his mental state.

The jury started deliberating Monday afternoon.

The trial heard from dozens of witnesses over six weeks, including three psychiatrists who testified that they believed Kachkar was psychotic at the time he killed Russell.

People who are found not criminally responsible are sent to mental health facilities for an indeterminate period of time and can be released only when a review board finds they aren’t a significant threat to public safety.