Former Ontario attorney general Michael Bryant is shown in the back of a police cruiser in Toronto on Monday night. (Tony Smyth/CBC)

The man once touted as a future premier of Canada's largest province is now facing charges involving the death of a cyclist on one of Toronto's busiest streets.

"Michael James Bryant, 43 years of age, of Toronto, is now charged with criminal negligence causing death and dangerous operation of a motor vehicle causing death," said Toronto police Sgt. Tim Burrows at an impromptu news conference outside the headquarters of the force's traffic division.

The cyclist has been identified as Darcy Allan Sheppard, 33, of Toronto.

A former attorney general of Ontario, Bryant was released under unspecified conditions on his own recognizance. Burrows said Bryant had "absolutely not" received any preferential treatment.

Bryant will make a court appearance on Oct. 19 in the case.

Criminal negligence causing death carries a maximum sentence of life in prison, while dangerous operation of a motor vehicle causing death has a maximum penalty of 14 years behind bars.

The Globe and Mail reported that the cyclist involved in the collision had been drinking, and had been investigated by police earlier in the evening when an ex-girlfriend called police. The Globe said the man was not charged in connection with the drinking.

Cyclist Darcy Allan Sheppard, 33, worked for a courier service and was the father of an infant son. (Facebook)

Bryant was an Ontario cabinet minister until May of this year when he stepped down to take the job as president and CEO of Invest Toronto, an arm's-length agency set up by the City of Toronto to promote investment.

Until then, the man who became the youngest attorney general in Ontario history had been frequently mentioned as a possible successor to Premier Dalton McGuinty as leader of the province's Liberals.

But Bryant's future is unclear following the death of a cyclist on Bloor Street West near Bay Street on Monday night.

According to police, Bryant was driving his black Saab convertible at about 9:45 p.m. when he and the cyclist became involved in an altercation.

Police said the incident quickly escalated.

Citing an unnamed police source, Canadian Press reported that on the evening of the incident, Bryant was out with his wife, Susan Abramovitch, for dinner to mark their 12th anniversary.

"There was some sort of altercation between the two people involved in this investigation, which has ended in, unfortunately, the death of a cyclist," Burrows said.

Burrows described what led to Sheppard's death as a "minor collision" involving the bicycle and the Saab.

"The cyclist ended up on the side of the car, holding on, and the driver continued along, driving westbound on Bloor Street."

Witnesses said Bryant crossed lanes of traffic to the south side of Bloor Street, still heading west.

Burrows could not explain why Bryant allegedly drove onto the curb.

"I don't want to try to say why [he] did that, only [he] knows exactly why, but he was travelling westbound in the eastbound lanes," he said.

A number of witnesses have come forward, police said, and investigators want anyone else who saw anything to contact them.

"We had seven witnesses that identified themselves to police last night, having seen the events that transpired. As in any investigation, however, the more witnesses we have, the better," Burrows said.

The witnesses said it appeared as though Bryant was attempting to knock Sheppard off the car by brushing against trees and mailboxes on Bloor Street approaching Avenue Road. Burrows said Sheppard was "essentially a pedestrian," having left his bicycle.

Police said Sheppard sustained severe injuries after striking a mailbox and a tree while still hanging on to the car.

Former Ontario attorney general Michael Bryant told reporters in Toronto on Tuesday that he wants to offer his 'deepest condolences' to the family of cyclist Darcy Allan Sheppard. (Darren Calabrese/Canadian Press)

He was dragged and then run over by the car's rear wheels.

Sheppard was rushed to Toronto's St. Michael's Hospital but was pronounced dead a short time later.

Other evidence police have collected includes security camera images from stores along one of Toronto's wealthiest business strips.

"We actually have viewed two videos that were provided to us by two different businesses along Bloor Street. We have officers right now on Bloor Street canvassing some of the other stores ... to see if they have any video that their systems may have captured," Burrows said.

Police said several 911 calls were made during the incident. One call came from Bryant while he was still in the vehicle.

Police spotted the Saab after it pulled into the nearby Hyatt Hotel. Bryant was later seen in the back of a police cruiser.

The head of the city's high-profile investment agency spent the next 14 hours in police custody answering questions.

Notes of remembrance are posted near the scene of Darcy Allan Sheppard's death. (Patrick Morrell/CBC)

When he emerged from the police station Tuesday, he offered his condolences to the Sheppard family and then asked to be left alone.

Bryant was first elected as the Liberal MPP for St. Paul's in 1999 and won re-election in 2003 — becoming the province's youngest-ever attorney general at the time — and again in 2007. He also served as aboriginal affairs minister and minister of economic development.

Bryant is a Harvard-trained lawyer who clerked at the Supreme Court of Canada and later taught law at the University of Toronto, Osgoode Hall and King's College, London. His wife is also a lawyer. They have two children.

Bryant resigned from politics three months ago to become president and CEO of Invest Toronto, which is chaired by Toronto Mayor David Miller.

The byelection to replace Bryant as MPP for the midtown riding is scheduled for Sept. 17.