In the wake of the public outcry over the shooting of Sammy Yatim on a Toronto streetcar last month, a former police officer who shot and killed a robbery suspect says it's best to wait for the findings of the investigation into the shooting before drawing any conclusions.

"It's fine to demand answers but there is a period of time that is required for due process to occur," Syd Gravel, a retired staff sergerant from the Ottawa Police Service said in an interview with host Alison Crawford on CBC Radio's The House.

"But we have to be careful from the court of public opinion where we start demanding answers before the investigation is complete."

Ontario's Special Investigations Unit has assigned eight officers to look into the circumstances surrounding the shooting of the 18-year-old Yatim, who was shot nine times and then tasered by police.

Ontario Ombudsman Andre Marin has said his office is conducting a preliminary review to determine if a broader investigation by his office is warranted.

Flashbacks and frustrations

Gravel says the shooting of Yatim has brought about a lot of flashbacks to the time, 26 years ago, when he shot and killed a robbery suspect after he refused a command and made a move Gravel deemed was a threat to his partner.

In the aftermath of that shooting, which Gravel said nearly destroyed his life, one of the things he found most frustrating was the questions and judgment he faced by the public, close friends and family. His father even questioned his decision, asking him if he couldn't have just shot the suspect in the hand.

"It's difficult because you'd like to be able to answer," Gravel said. "When the investigation is going on you're not allowed to answer." 

The investigation into that shooting took six years to complete, with no charges brought against Gravel.

Gravel went on to become the staff sergeant in charge of training, and retired in 2009. Later this month his second book, How To Survive PTSD and Build Peer Support, will be published.

Listen to the full interview with Syd Gravel on CBC Radio's The House.