Homicide detectives are investigating after York Regional Police Const. Garrett Styles died of injuries he incurred when he was dragged and pinned under a vehicle during an early morning traffic stop north of Toronto.

While he was trapped under the minivan, Styles, who would have celebrated his 33rd birthday on Sunday, managed to speak with a police dispatcher.

"I got a car on top of me," he tells the dispatcher. "We've got help on the way," the dispatcher responds. "Just sit tight."

Despite being badly injured, Styles expresses concern for the four youths trapped inside the van on top of him.

"And, uh, I got these people inside the van. I don't know how they're doin'."

Styles was a seven-year veteran of the force. He is survived by his wife Melissa, who is a civilian employee of the York Regional Police, and two children, a daughter aged 2½ and a nine-week-old son.

The incident occurred just before 5 a.m. ET Tuesday on Highway 48 near Herald Road in the town of East Gwillimbury.

In a press conference Tuesday afternoon, York Regional Police Chief Eric Jolliffe said Styles had pulled over a 2005 Dodge Caravan and was at the driver's side door when the vehicle suddenly accelerated.

Jolliffe said Styles was dragged approximately 300 metres before the vehicle lost control and rolled over, pinning Styles.

He was rushed to Southlake Regional Health Centre in Newmarket, where he was later pronounced dead.

'I got a car on top of me!' While he was pinned under the minivan, Const. Garrett Styles was able to speak with a police dispatcher. The audio file (top left) includes an edited version of that conversation. The blocks of silence were created in the editing process. An excerpt of the officer's conversation with the dispatcher follows: Const. Styles: [desperate tone] I got a car on top of me, help! Dispatcher: Car on top of him, 10-4, got an ambulance on the way. Const. Styles: [heavy breathing, difficulty speaking] I don't have any... [heavy breathing, inaudible] Dispatcher: [anxious tone] 10-4, we've got help on the way, just sit tight. Dispatcher: Units, 10-4, en route. Const. Styles: We might have some other people injured here, too. I dunno. Dispatcher: Yuh, 10-4, we've got help on the way. Ambulance and fire are coming. Policeman #2: [siren in background] Garrett, keep talking to us. Const. Styles: [on-and-off pressing of radio button, no voice] Dispatcher: Just keep talking to us, tell us what's going on. Const. Styles: I got a van on my waist. Ahh, I don't know. It hurts. And, uh, I got these people inside the van. I don't know how they're doin'.

The unlicensed driver, a 15-year-old male from York Region, is in critical condition at Toronto's Hospital for Sick Children. He suffered massive head injuries and CBC News has learned there are fears he may have paralysis.

Three passengers in the van, also youths, are co-operating with police, Jolliffe said.

Police have not released information about possible charges.

The York police chief described Styles as a "a dedicated professional, who always had time to assist others."

"This is indeed a significant loss to York Regional Police and the citizens of York region," he said at early afternoon press conference. "Every member of York Regional Police is devastated by this loss."

Styles joined the force as a cadet in training in December 2003. He became a constable in May 2004. He recently started working in Newmarket, Aurora and East Gwillimbury after initially working in Richmond Hill.

Styles comes from what Jolliffe described as a "close-knit policing family." His father, Det.-Sgt. Gary Styles, retired in January after serving 33 years with the force.

The scene where York Regional Police Const. Garrett Styles was injured after being struck by a vehicle during a traffic stop at Highway 48 and Herald Road, east of Newmarket, Ont., on Tuesday. He later died in hospital. (Aaron Vincent Elkaim/Canadian Press)

Condolences offered

Ontario Premier Dalton McGuinty offered his condolences to the Styles family.

"I was deeply saddened by the death of Const. Garrett Styles, who was killed this morning in the line of duty," he said in a statement on Tuesday.

"We ask a lot of our police officers. We ask them to uphold our laws, protect our homes and, if need be, put our safety before theirs. Our police, and their families, agree to protect us and ours knowing that doing so may mean paying the ultimate sacrifice."

Progressive Conservative Leader Tim Hudak said in a statement that his party's thoughts and prayers are with the Styles family.

Const. Garrett Styles had seven years of service with the York Regional Police. (York Regional Police)

"When we lose one of our officers, we’re reminded of the risks they face as they work to keep us out of harm’s way, and the rare combination of skill and bravery that each one brings to the job," he said in a statement.

The president of the Ontario Association of Chiefs of Police, Matt Torigian, said Tuesday many police officers will be stopping to reflect on colleagues who have died in the line of duty.

That includes Toronto Sgt. Ryan Russell, who was struck and killed by a stolen snowplow in January, said Torigian, who is the chief of the Waterloo Regional Police Service.

The last officer from York region to lose his life in the line of duty was Det.-Const. Robert Plunkett, who died in August 2007 while investigating air bag thefts. Plunkett died on a Markham street after being pinned against a tree when a suspect vehicle suddenly and unexpectedly reversed.

A sentencing hearing for Nadeem Jiwa, who was convicted of manslaughter in Plunkett's death, continues on Wednesday.