WINNIPEG -- A man who allegedly fell asleep on a bus and, when roused, refused to leave has been charged in the fatal stabbing of a transit driver.

Brian Kyle Thomas, 22, of Winnipeg is facing charges including second-degree murder, possession of a weapon and failing to comply with a probation order.

Court records show Thomas has convictions dating back to 2012 for crimes that include weapons offences, assault and robbery. He has been in and out of custody and was last on probation in November.

Police say driver Irvine Jubal Fraser had finished his route at the University of Manitoba in the early hours Tuesday. Only one passenger was left on the bus.

"This individual was asked ... by the operator ... many, many times to exit the bus, that (it) was the end of the route and it was time to exit," police spokesman Const. Jason Michalyshen said Wednesday.

"Sadly, things just escalated from that point."

He said the passenger walked to the front of the bus and the driver escorted him off. A scuffle continued outside and the driver was stabbed multiple times in the upper body.

The suspect was arrested trying to cross the frozen Red River near campus. Fraser, 58, died in hospital.

Michalyshen couldn't say if the passenger had been sleeping or was impaired at the time.

John Callahan, president of the Amalgamated Transit Union Local 1505, said the passenger was with a group who had been drinking. The others got off at a different stop and left him sleeping, said Callahan.

"When the operator attempted to wake him up, he didn't know where he was, where his buddies were, and became agitated," he said.

"The guy was out of it."

Callahan said another bus had stopped behind Fraser's, but because most buses don't have rear windows, the driver couldn't see what was happening inside Fraser's bus. When the confrontation spilled outside, the driver called for help.

Colleagues have described Fraser as a popular guy who planned to retire next year. Callahan and others with the union visited his widow Tuesday to offer condolences and drop off sandwiches. He said the woman was very distraught. The couple lost a daughter a few years ago, he said.

Fraser's death marks the first time a Winnipeg bus driver has been killed during an assault and not in a traffic accident.

Statistics released by the union show there were 60 assaults on Winnipeg transit drivers in 2015, a jump of 54 per cent from the previous year. The number went down to 45 assaults in 2016. Callahan said that's partly due to undercover officers who started riding buses that year and intervened in some disputes.

City officials have said they plan to meet with the union to discuss ways to improve bus safety.

Buses are already equipped with surveillance cameras, GPS systems and emergency buttons -- something Callahan said Fraser didn't have a chance to push. There have been talks about putting up shields for drivers, but Callahan would rather see an entire redesign of buses that puts drivers in an enclosure.

He also suggested that since many passengers do fall asleep on buses, there should be a policy for drivers on what to do.

"Some say you shout out to them. Some say you make sure they're breathing and call it in. There is no ... defined method of doing this and there needs to be."

He also said routes shouldn't end in the middle of the night in outlying areas, but in a central location with on-site inspectors who can help wake passengers and escort unruly ones off.

"It should not be a solo effort. It's a recipe for disaster."

-- By Chris Purdy in Edmonton