Ontario's ombudsman is going to examine the way that a provincial ministry sets guidelines for police on how to de-escalate situations in the wake of Sammy Yatim's fatal shooting on a Toronto streetcar.

Yatim was shot dead by police in the early minutes of July 27 on a streetcar that was stopped on Dundas Street West, near Bellwoods Avenue. Witnesses have said that he was holding a knife when he was on the streetcar.

The shooting was recorded on video by several sources. Footage that has been posted online has been viewed hundreds of thousands of times.

The 18-year-old's death at the hands of police shocked many residents of Toronto and prompted a protest march days later in which hundreds of people participated.

Toronto police Const. James Forcillo, the officer who fired the shots, has been suspended from duty. Ontario's Special Investigations Unit is now probing the circumstances of the fatal shooting.

The head of the Toronto Police Association has urged the public not to draw conclusions about what happened until all the facts are known.

The public nature of Yatim's death has "raised important questions about broader issues," Ontario Ombudsman André Marin told reporters at a news conference on Thursday afternoon.

That's why Marin — himself a former director of the SIU — said his office has decided to move ahead with an investigation into the guidelines the province's Ministry of Community Safety and Correctional Services gives to police "for de-escalating situations that could result in the use of force."

Following Yatim’s shooting, Marin said he had his staff review provincial guidelines as well as police practices and training.

His staff have also looked back at similar cases from the past that occurred in Ontario and elsewhere.

Marin said that process has convinced him that "a full investigation is warranted."

The ombudsman said that the police shootings that have occurred in Ontario over the past two decades have remarkable similarities to one another, as do the recommendations that come out of the inquests that followed them.

"It seems to be like Groundhog Day. Inquest after inquest, police shooting after police shooting," Marin said.

Madeleine Meilleur, the minister of community safety and correctional services, said that her ministry will "co-operate fully" with the ombudsman’s investigation.

Watchdog outs online 'troll'

During his press conference, Marin was asked about messages that had been posted on Twitter by someone claiming the ombudsman was "a carded member" of al-Qaeda.

Ahead of the news conference, Marin had identified the person behind the tweets as a Durham police officer.

On Twitter, the ombudsman described the officer as using a "troll" alias, in apparent reference to people who lurk in anonymity online and make controversial comments.

Asked why he took that step, the ombudsman said that he didn’t believe the person sending out the tweets should be able to do so anonymously.

"These are pretty serious allegations and to hide behind an anonymous account to propagate hate tweets is just not right," he said.

Marin said he doesn't think the tweets are related to his interest in the Yatim case, though he did not elaborate as to why he thinks that.

With files from The Canadian Press