Police close off a stretch of Victoria Park Avenue as the investigate the shooting of a man outside a TTC bus. (Ivy Cuervo/CBC)

The province's Special Investigations Unit is looking into an incident in which a man was fatally shot following an altercation with Toronto police in the city's east end.

The shooting occurred at around 3 p.m. Sunday on Victoria Park Avenue at Biscayne Boulevard, just north of Eglinton Avenue East.

Pickering native Reyal Jensen Jardine-Douglas, 25, was shot multiple times, police confirmed. He was rushed to Sunnybrook Hospital, but died a few hours later.

Authorities are releasing few details about the incident, but Monica Hudon, a spokeswoman for the SIU, confirmed it happened after officers started following the southbound TTC Number 24 bus on Victoria Park Avenue.

"A short time later officers pulled over the bus and Mr. Jardine-Douglas exited the bus," she said. "There was an interaction between him and the officers and he was shot more than once."

It is not immediately clear why police were following the bus. The SIU has also not provided any details of the nature of the interaction between police and Jardine-Douglas, although hours after the shooting, a knife with a black handle could be seen on the road a few feet away from the bus.

Jason Brown and his girlfriend live in a building minutes away from where the shooting happened. He said she saw the whole thing unfold.

"She was in the alleyway in front of the guy and the cops shot the guy once. He dropped on the ground. The next partner came and gave three more to the guy," Brown said.

Several other bystanders say they heard five loud shots.

Hudon said the SIU, an independent civilian agency that investigates incidents involving police where people are seriously hurt or killed, has appointed investigators to look into the incident.