Ontario's police watchdog has cleared Ottawa police of wrongdoing in a 2016 crash that killed two people and seriously injured another.

The crash happened in the early morning hours of April 12, 2016.

At about 1 a.m., an Ottawa police officer in a cruiser tried to stop a car at Cumberland and George streets in the ByWard Market for a provincial matter, the Special Investigations Unit said in a media release issued Wednesday.

That officer called for assistance when the driver of the car fled, and he and another officer in a separate cruiser activated their lights and sirens to pursue the car east on Rideau Street. The 39-year-old man driving the car drove at about 60 km/h and was not stopping for red lights, the SIU said.

Officers ordered to stop pursuit

About 32 seconds after the first officer broadcast details about the call, a road sergeant ordered officers to stop their pursuit. One of the officers stopped at Rideau and Augusta streets, and the other came to a stop near Rideau and Chapel streets — both less than a kilometre away from the initial attempted traffic stop.

Alex Cross, 24, was pronounced dead the day after the crash. (Facebook)

The man driving the vehicle continued to flee at a high rate of speed east along Rideau, taking Cummings Bridge over the river, the SIU said.

He didn't slow down when he turned right, through a red light, onto North River Road, and then went through another red light turning left onto McArthur Avenue.

At the intersection of McArthur Avenue and Vanier Parkway, the driver once again passed a red light and struck another vehicle that had been heading south, the SIU said.

'No basis whatsoever' to hold officers responsible

The 24-year-old driver of the vehicle that was struck died, and a 21-year-old woman in the passenger seat suffered serious injuries.

The driver of the vehicle that had been pursued succumbed to his injuries in hospital in December 2016, months later.

"There is no basis whatsoever to hold either of the two subject officers responsible for the terrible outcomes of the motor vehicle collision," SIU director Tony Loparco is quoted saying in a media release.

"The pursuit was short-lived, having been terminated by the road sergeant. The driver operated his vehicle at hazardous speeds through multiple red lights for over 1.47 km with no one following him. He showed a wanton and reckless disregard for all other people using the roadway. As a result of the prudent decision of the road sergeant, the two subject officers cannot be said to have causally contributed to the collision in a legal sense."

The SIU investigates cases of death, serious injury and sexual assault involving police in Ontario.