Ralph Thistle joined the Toronto Police service in 1977.

Over the course of his 30 year career he worked in a variety of jobs including investigating murders in the Homicide Unit and training fellow officers and recruits as a firearms instructor.

Const. Thistle left the police service in June 2007, one week short of his eligible retirement date.

In the last years on the job, Thistle says he was homeless, suffered from PTSD and depression and was an alcoholic. He even ended up in jail himself in 2011.

He says his downward spiral started after he'd been on the job for seven years, when in 1984 he was confronted by a bank robbery suspect he believed was armed and ready to kill him. Thistle shot the young man, who later became paralyzed.

Now, he is a recovering alcoholic who has been sober for three years. He's on medication, and gives talks about his experience to help others who may be facing similar troubles.

Last week CBC's John Lancaster spent the day with the former police officer talking about his life.