The family of an 18-year-old who died on Wednesday night after a brief police chase near the York University campus says they believe police beat him to death.

Toronto police officers were trying to stop a vehicle on Steeles Avenue West near Founder Road when two people jumped out of the car and fled, the province's Special Investigations Unit said in a news release.

One of the people being pursued, Junior Alexander Manon, 18, collapsed and was taken to hospital where he was pronounced dead, the SIU said.

But Manon's family and friends, who met Friday night in a candlelight vigil outside the coroner's office, dispute that version of events.

Selwyn Pieters, a lawyer who represents the family, said he has spoken to witnesses who allege the police used excessive force.

'His eyes were black and blue'

Pieters also said he viewed Manon's body and saw what he believed was further evidence that Manon did not collapse on his own.

"There was blood all over, he had a neck brace on and his eyes were black and blue," said Pieters.

"The issue of a heart attack is a fiction. It seems he died from physical force."

The SIU, the arm's-length agency that is called in any time there is a death or serious injury involving police and the public, is investigating the case.

No charges have been laid, but an SIU spokesperson said two officers have been designated "subject officers" — meaning, according to the SIU website, officers "whose conduct appears, in the opinion of the SIU director, to have caused the death or serious injury under investigation."

Another eight others have been designated "witness officers" in the case, the spokesperson said, meaning they were present but not directly involved in the incident being investigated.