There was no wrongdoing in the Aug. 10 killing of Aaron Driver, an ISIS supporter gunned down by RCMP as he detonated a bomb in a Strathroy, Ont., taxi, a police investigation has found.

Driver was shot and killed by police after he detonated the device outside his sister's home in the town, 35 kilometres west of London. RCMP were responding to a tip from the FBI about an imminent terror threat involving Driver.

Strathroy-Caradoc police and the Ontario Provincial Police, which conducted the investigation into the RCMP shooting, said the use of force that afternoon was justified.

"Fearing for their safety, and believing that Mr. Driver would detonate a second device, the RCMP shot Mr. Driver fatally wounding him," the Strathroy-Caradoc Police Service release states.

The force says an independent review of the investigation by Crown prosecutors has upheld the probe's conclusion.

Taxi driver narrowly escapes

Driver, reportedly an Islamic State in Iraq and Syria sympathizer, was planning an attack in a public place, police said.

Mounties worked with several law enforcement groups, including the OPP and London police, when they surrounded the home on Park Street where Driver was known to live with his sister.

A taxi pulled into the driveway in the afternoon, and Driver exited the house, carrying a backpack. After Driver got into the back seat of the cab, police blocked the car from leaving.

As officers approached the vehicle, Driver detonated a bomb, according to the release.

Taxi driver Terry Duffield narrowly avoided the explosion by diving out of the cab moments before Driver detonated his device.

Considering legal action

Duffield's lawyer Kevin Egan, says the taxi driver is disappointed with the investigation and considering legal action against police.

Egan also questions why police involved in the operation to take down Driver conducted the investigation.

"We're really not surprised that the police investigating themselves came to the conclusion they were justified in shooting Mr. Driver," he said.

The province's Special Investigation Unit, which investigates incidents involving police, was contacted after Driver's killing, but it did not conduct its own investigation, according to Const. Mark Thuss with Strathroy police.

The SIU was not immediately available for comment.

Even if SIU was brought in, though, Strathroy would have done its own investigation, Thuss explained.

"In a case like this, with an officer involved shooting, it's common that there is a parallel investigation," Thuss said.

The RCMP did deferred all questions from CBC News to Strathroy police and the OPP.

Egan wants to know why police allowed Duffield to get close to the home.

"We had hoped the people doing the investigation might look at why Mr. Duffield was put in harm's way," Egan said. "There's not one word why Mr. Duffield was allowed to be put in that situation."

Egan said his client suffered physical and psychological injuries from the incident. Duffield tried to return to work within a week of the shooting, but he broke into a sweat and vomited when he turned the ignition.

"My whole body started to shake like a leaf in the wind," Duffield told CBC News at the time.