The mother of a teenager who died after a weekend crash that claimed the lives of two other young victims is questioning the safety and wisdom of police chases.

"(The incident took) three lives. I just don't understand, where's the justice? Is there a God?" asked Jannett Scott-Jones, crying uncontrollably.

"I just don't understand. This is senseless ... I'm just so horrified."

Scott-Jones made the difficult decision to take her 17-year-old daughter Aleisha Ashley off life support on Sunday night. Ashley was pronounced brain dead at Sunnybrook Health Sciences Centre.

Ashley's best friend Monique McKnight, 16, also died in the violent crash in Rexdale early Saturday morning.

McKnight and Ashley were travelling together in a taxi when a fleeing vehicle struck them near Finch and Islington avenues.

The driver of the stolen Acura, 15-year-old Chevon Josephs, was also killed in the accident. He was allegedly being pursued by police before the crash occurred.

Police spotted Joseph racing down the street when they were in the area to respond to a gun call.

The tragedy has prompted calls to the Ontario government to investigate how future crashes can be prevented.

Premier Dalton McGuinty on Sunday said police should consider reviewing their protocols when pursuing suspects.

"Police chases occur frequently, but infrequently they result in some kind of tragedy,'' McGuinty said.

"But I think every time something like this happens, it's an opportunity for police protocols to be reviewed, to ensure that a chase doesn't compromise public safety.''

Investigators with the Special Investigations Unit (SIU) are continuing to probe the extent of police involvement in the collision.

Toronto police won't consider any changes to police chase protocol until the SIU investigation is complete, Toronto Police Board chairman Alok Mukerjee told the Toronto Star on Monday.

Mukerjee said there were 245 police chases last year. He noted many of the pursuits don't last very long and injuries or fatalities are rare.

Police Chief Bill Blair, meanwhile, issued a statement Monday afternoon regarding the deadly incident.

"I want to take this opportunity to express my condolences and sympathy to the three families for their tragic losses. Our thoughts and prayers are with them," the statement read.

Blair said the Police Services Act requires the force to conduct a review after the SIU investigation.

"We have a duty to investigate and apprehend those who are suspected of breaking the law. We cannot always control their dangerous conduct, but we will do everything we can to ensure that such tragedies can be avoided where possible."

Funeral plans for McKnight and Ashley have not yet been finalized, but the girls' mothers plan to bury the teens together.

With a report from CTV's Janice Golding and files from The Canadian Press