Toronto Police Chief Bill Blair said the death of Sgt. Ryan Russell while trying to stop a stolen snowplow Wednesday is a reminder of “how dangerous our work can be."

Blair had the “grim task” of telling the 35-year-old officer’s family that Russell had been killed in the line of duty -- the force’s first such death since 2002.

"He is a hero of the Toronto Police Service who went out this morning to do his job. And in doing his job, he gave his life,” the chief said.

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When Blair spoke earlier at St. Michael's Hospital, he told reporters: "This is the worst of days for the Toronto Police Service."

Mike McCormack, president of the Toronto Police Association, called the tragedy “our worst nightmare."

Russell leaves behind a wife and a two-year-old son. The former member of the guns and gangs task force, promoted to sergeant at downtown's 52 Division about six months ago, is the son of a former Toronto police officer.

What happened

Police were alerted around 5:30 a.m. that a privately owned snowplow had been stolen from the Dundas and Parliament Streets area.

"Somebody ran across the road with no shoes on and just jumped in the truck and took off," said plow owner Peter Tolias.

Police attempted to stop the vehicle after it was spotted driving erratically through the downtown core on Avenue Road, just north of Bloor Street, just after 6 a.m.

At one point, the truck backed through the front window of a luxury car dealership near Avenue Road and Bloor Street before crashing into a taxicab. According to the taxi's driver, the truck reportedly turned around and struck his cab again before continuing its journey northward.

Russell was struck by the snowplow at the intersection of Davenport and Avenue Roads. The collision left him pinned against his cruiser as he tried to bring the snowplow to a halt.

CTV Toronto's Austin Delaney said as of noon, Russell's car was still running.

Fellow officers and EMS personnel tried to provide CPR at the scene as the officer lay on the snowy road with a terrible head injury.

Rory O'Neill, one of the first paramedics to arrive on the scene, said attempts to revive Russell, who was already without vital signs, appeared to happen in slow motion.

"You're talking out loud asking guys for input: what can you do, what do you think, let's try this," O'Neill told CTV Toronto. "And the whole time you're thinking it's taking too long to get there. Three minutes to get here, four minutes to get down to St. Mike's and it seems to take forever. And you know that there's noting you can do, he needs a surgeon, he needs the trauma unit to do the best that they can. And it's frustrating."

Paramedics rushed Russell to the trauma unit, but the 11-year police veteran's life could not be saved.

Homicide investigators remained at the scene for much of the day Wednesday, and police say Avenue Road between Davenport Rd. and Dupont St. could be blocked off for three days.

Takedown

The suspect drove the snowplow away from the scene of the crash and continued west, crashing into parked cars and buildings.

Police followed the truck with the help of Tolias by using the vehicle's GPS device.

The nearly two-hour pursuit stretched for more than 10 kilometres. It finally ended shortly after 7 a.m. when the truck struck a vehicle and came to a stop in the Humberside Avenue and Keele Street area after heading south on Keele.

Motorists told CTV Toronto's John Musselman they were forced to swerve to avoid being hit by the snowplow.

"He was heading right towards me," Pierpaolo Miele said, who couldn't get out of the way. "That's when he hit the back passenger side and spun me out."

Then the police's Emergency Task Force arrived on the scene.

"Pops -- pop, pop, pop," said witness John Wilson about the sound of gunfire from police officers trying to apprehend the suspect. "I mean, the car had tried to move."

Witnesses report hearing as many as nine shots fired.

An ETF officer suffered a hand injury during the takedown, Blair said.

Toronto EMS took the suspect to St. Michael's Hospital, the same hospital where Russell was pronounced dead. News footage taken at the hospital showed the suspect being removed from the ambulance on a gurney without shoes on his feet.

In a news release issued Wednesday afternoon, the provincial Special Investigations Unit said the suspect has undergone surgery and is recovering in the intensive care unit.

The SIU is responsible for reviewing cases in which people have suffered injuries or died as a result of contact with police.

"The SIU has designated one officer as a subject officer and nine officers as witness officers. Four civilian witnesses have been interviewed," the release said.

Carm Piro, a spokesperson with the SIU, said the agency is co-ordinating its efforts at the scene with Toronto Police investigators.

"They obviously have a homicide investigation on their hands here, and we have to co-ordinate what's being seized and what's being processed here at the scene to preserve any evidence to support the investigation," Piro said.

Blair said no charges have been laid yet against the suspect, and the investigation is ongoing. CTV Toronto's Tamara Cherry reported that police know little about the suspect, who was not carrying any identification. However, late Wednesday they learned that he is 44 years old.

Details on funeral arrangements for Sgt. Russell will likely be known on Thursday, Blair said.

With reports from CTV Toronto's Paul Bliss, Austin Delaney, John Musselman and Tamara Cherry