During the call, which came in just before 6 a.m. on Sunday, an unidentified man claimed to be hiding in a closet while his father roamed the house in a murderous rage.
"My dad Francis, he's gone crazy. He's got his gun out," the man said.
The caller claimed his father had shot and killed the caller's mother and was now looking for him.
"He's locked us in the house.… He has schizophrenia and it's really bad," he said, blubbering.
The caller claimed the gunman had been drinking, had not taken "his medicine" and was armed with "a big assault rifle — I think it's an S-22."
The 911 operator assured the man that help was on the way. After a few minutes, there is what sounds like a scuffle and the line goes quiet.
(Warning: Some listeners may find the audio disturbing.)
The hoax — an example of what is known as "swatting" — led an emergency task force team to the Richmond Hill home of Vincent Yan and family, who were sleeping quietly.
After a few tense and terrifying minutes as police arrived in full force, it became clear that the family were the victims of a cruel prank, and a criminal offence.
Swatting has become a plague for law enforcement, with similar incidents occurring across North America. It is thought to have originated in online gaming.
Gamers have been known to make fake calls to police and watch on screen as ETF or SWAT teams burst into their friends' homes with guns drawn.