A woman charged with criminal negligence causing death was granted bail today in Toronto after a young boy was left in a hot car and later died in hospital.

Toronto police say Zeljna Kosovac, 50, was responsible for dropping the boy off at a care facility on Thursday.

The boy, who is three and not four as initially reported by police, was found at about 2:30 p.m. ET the same day in the car parked outside a west-end condo tower.

Toronto Const. David Hopkinson said on Friday that the boy was discovered when someone passing by became concerned and broke one of the car windows to get him out.

A car seat and other debris at the scene where the child was found. (Guillaume Cottin/Radio-Canada)

He was unconscious, and later died in hospital.

The temperature on Thursday was 26 C, with a humidex of 31. Police wouldn't confirm how long the boy was alone in the car.

Kosovac declined to speak with reporters as she exited the courthouse.

A post-mortem on the boy was set to take place Friday.