A police investigation has found RCMP were justified in fatally shooting a terrorist sympathizer during a confrontation in southwestern Ontario earlier this year.

Aaron Driver died in an encounter with RCMP in Strathroy, Ont., in August, after making a martyrdom video that suggested he was planning to detonate a homemade bomb in a Canadian urban centre during morning or afternoon rush hour.

The Ontario Provincial Police Criminal Investigation Branch and the Strathroy-Caradoc Police Service conducted an investigation into the shooting of Driver to determine if the use of force in the incident was legally justified.

Strathroy-Caradoc police said Wednesday that the investigation concluded the use of lethal force was justified.

An independent review of the investigation by Crown prosecutors upheld the probe's conclusion, the force said.

"The specific mandate of the investigation was to scrutinize the shooting death to determine if the use of force was legally justified in Canadian Law," the force said in a release. "The Crown prosecutor upheld the investigative conclusion that the use of lethal force was justified, and therefore non-culpable."

Canadian authorities were tipped off about Driver's activities by the FBI and confronted him hours later.

The FBI tip included a video of a masked Driver railing against western "enemies of Islam" and warning that the only solution would be the "spilling of your blood."

In announcing the result of their investigation Wednesday, Strathroy-Caradoc police recounted details of the encounter with Driver that ended with his death.

The 24-year-old Driver had come out of a residence with a backpack and got into the rear seat of a waiting cab when RCMP officers blocked the vehicle from leaving the area, Strathroy-Caradoc police said.

RCMP directed the taxi driver and Driver to exit the vehicle, the force said, but as an officer approached the cab, Driver detonated an improvised explosive device.

"Mr. Driver exited the vehicle and failed to comply with the police and their directions. Fearing for their safety, and believing that Mr. Driver would detonate a second device the RCMP shot Mr. Driver fatally wounding him," Strathroy-Caradoc police said.

At the time, Driver had been under a court order not to associate with any terrorist organizations or to use a computer or cellphone. But he wasn't under continuous surveillance despite concern he might participate or contribute to the activity of a terrorist group.

He had moved to Strathroy earlier this year to live with his sister.

Driver's father has said his son was a troubled child but appeared to have turned his life around after converting to Islam.

Wayne Driver has said his son stopped doing drugs, had a full-time job, a girlfriend and was civil again after years of problems that began when his mother died when the youngster was seven.

But he said CSIS contacted him in January 2015 about disturbing posts his son had made on social media.

Aaron Driver was picked up by police in Winnipeg in June 2015.

He was held on a peace bond due to fears he would "participate in or contribute to, directly or indirectly, the activity of a terrorist group to facilitate or carry out a terrorist activity."

He was released under a raft of conditions in February.