Brandon Crisp, 15, is shown here in an undated family photo. (Barrie Examiner/Canadian Press)

A Barrie, Ont., high school paid tribute to 15-year-old Brandon Crisp on Thursday, as investigators awaited an autopsy on a body believed to be that of the teenager who has been missing for three weeks.

The coroner's office announced the autopsy on a body of a male teen discovered on Wednesday won't be performed until Friday morning. Police believe the body is that of Crisp, who left home after a dispute with his parents over a video game, but authorities are awaiting pathology results to make a confirmation.

The flag at St. Joseph's High School flew at half-mast, as students met with grief counsellors to help them cope with the loss. White ribbons adorned the schools doors as symbols of purity.

Many students appeared visibly distraught on leaving for the day.

"It's affected everyone," Sergio, a student representative and one of Crisp's Grade 10 classmates, told reporters outside the school.

"I've known Brandon since Grade 4. I've grown up with him."

The teen disappeared on Oct. 13 after arguing with his parents over a favourite Xbox video game, Call of Duty 4: Modern Warfare. They had taken the game away from him because they felt he had become obsessed with it and his many connections in the online gaming community.

Principal Matt McCann said the school would accelerate plans to offer programs on the safe use of technology in the wake of the tragedy.

"Students are so tech literate, and they're ahead of us, as adults, but I think also with it comes another factor that they may not always be aware of — dangers," he said.

But some students at the school expressed skepticism about the educators' plans.

"It's a waste of time, everybody's just going to forget by the end of the day," said Michael Monk, 15. "I think it's not the fault of video games."

The body was discovered Wednesday morning by hunters in a field northeast of his hometown of Barrie. It was found in the Shanty Bay area where searches have been taking place since Oct. 20.

The autopsy results could also show how he died. Police have said they do not believe foul play was involved, but have not conclusively ruled it out.

"I think at this point, because it's so early in the investigation … we can’t rule foul play out at this point," Sgt. Dave Goodbrand of the Barrie police told CBC News.

Alyssa Whelen lights a candle near the site where a body believed to be Brandon Crisp was found on Wednesday. (Mark Wanzel/Canadian Press)

"Anything's possible. But at this point, I don’t think investigators have any reason to believe that the public is in danger but we just want to get out we obviously have a lot of work to do before we can rule out foul play issues."

Officers had been searching cornfields and the bush in the Shanty Bay area around Barrie where Crisp was last reported seen walking on the Oro-Medonte Rail Trail with his bicycle.

Crisp was sighted twice on the day he disappeared. His bicycle was found on Oct. 20.

With files from the Canadian Press