A 33-year-old man has life-threatening injuries after an altercation on a sidewalk in North Burnaby ended with him getting struck by a TransLink community shuttle bus.

Burnaby RCMP said officers were called to Hastings Street near Carleton Avenue around 5:45 p.m. for reports of an altercation between two men. But before they arrived, one of the men ended up off the sidewalk and on Hastings, where he was struck by the bus.

Cpl. Michael Kalanj said so far, Mounties don't know if the victim was pushed onto the road. 

"We want to determine if the man was in the roadway as a result of the altercation, or if it was something else. That’s the basic focus of the investigation," Kalanj told reporters Wednesday morning. 

A surveillance video from a nearby store obtained by CTV News shows two men squaring off to fight. As they come together, one of them stumbles backwards into the path of the shuttle bus.

According to employees at the store, police also have a copy of the video.

Burnaby RCMP’S Serious Crimes Unit is leading the investigation along with a criminal collision investigation team

Police are not commenting on what the altercation may have been about, and are still trying to determine if the two men know each other. Police would not say if either of the men are from Burnaby. 

Two people were initially arrested, but one was later released after it was determined he was a witness.

A 62-year-old man remains in custody, but has not been charged.

The community shuttle bus involved in the incident has visible damage to its front end. A tarp was placed over the bus by investigators just after midnight as police spent the overnight hours taking photos and measurements of the area.

Personal belongings lay on the road surrounded by police evidence markers not far from where the shuttle bus came to a stop.

Two eastbound lanes of Hastings Street near where the man was hit remained taped off by police early Wednesday afternoon, more than 18 hours after the crash.

The driver of the TransLink community shuttle bus involved in the incident is not being investigated and is receiving counselling.

The area of Hastings where the altercation happened was packed with shoppers and drivers at the time of the collision. RCMP say many witnesses watched as the man was struck, some of those witnesses are now being helped by victims services

"It was quite impactful for the witnesses who were there to see this kind of incident," Cpl. Kalanj said. 

Police are asking for additional witnesses and anyone with DashCam or surveillance footage from the area to come forward.

Authorities said they expect Hastings Street to fully re-open sometime on Wednesday afternoon.  

With files from CTV Vancouver's Jordan Jiang