A mere two days after a Windsor, Ont. police officer was killed on the job, thousands of people gathered at the provincial legislature Sunday morning for an annual ceremony to honour officers killed in the line of duty.

Windsor Police Constable John Atkinson was shot and killed Friday after confronting two teenagers at a convenience store. The 18-year-olds have been charged with first-degree murder.

During Sunday's ceremony at Queen's Park in Toronto, Ontario Lieutenant-Governor James K. Bartleman acknowledged the sacrifice made by Atkinson and others.

"Our hearts go out to his family and the Windsor police force for their profound loss," Bartleman said.

Also attending the ceremony were Windsor Police Chief Glenn Stannard and Ontario Premier Dalton McGuinty.

"We also remember in our thoughts, in our prayers Senior Constable John Atkinson, Windsor Police Service and his family," Stannard said. "(He) will be buried in Windsor on Thursday with full police honours."

The premier said Sunday's ceremony seemed like a small gesture in comparison to the sacrifices made by fallen officers.

"(But) it comes from the heart and it matters, it matters that we remember," McGuinty said.

Atkinson is the 719th Canadian peace officer to die in the line of duty.

Bruce Miller of the Police Association of Ontario says it is hard for a police service to continue after such a tragedy.

"They're your colleagues, you work with them 24 hours a day. And to lose somebody, it's hard to move forward.

"But the sacrifice they make it something that words just can't describe," he told CTV's Canada AM.

Since 2000, 48 officers have been killed on the job. Nine have been killed since 2005, including four RCMP officers ambushed by James Roszko in Mayerthorpe, Alta.

Teenagers charged

Charged for Atkinson's death are Nikkolas Robert Brennan and Coty Clifford Defausses. The suspects appeared in court Saturday and were remanded. Police believe the two teens were the only people involved.

"I am confident that we have the two individuals who participated in his murder in custody," said Insp. Greg Renaud, lead investigator in the case.

A nine-millimetre handgun was taken as evidence from the lawn of a nearby residence, police said.

Renaud said the suspects, one of whom is known to police, were both allegedly involved in illegal narcotics activity and were allegedly carrying crack cocaine when they were taken into custody.

They are also charged with drug trafficking. Brennan faces a weapons charge.

Building their case

Investigators located a woman who left the convenience store just prior to the shooting.

Officers made public appeals on Saturday for the woman to come forward, while stressing she was not a suspect but may have had information valuable to police

Windsor police have not provided details about their conversations with the witness.

With files from CTV's Austin Delaney and The Canadian Press