British Columbia's police watchdog, the Independent Investigations Office, has ordered a third-party review of the agency's investigation into the death of a retired soldier shot by RCMP.

Greg Matters, 40, was shot and killed after a 30-hour standoff with a police emergency response team on a rural property outside Prince George, B.C. in September 2012.

Matters was a soldier for 15 years, who served in the Bosnian conflict before returning to Prince George in 2009, and was being treated for post-traumatic stress disorder at the time of his death.

The Independent Investigations Office issued a report in April 2013, clearing officers of criminal wrongdoing.

That report said Matters was shot in the chest but a pathologist testified later at a coroner's inquest that Matters was shot in the back.

The office released a supplemental report last week that blamed the discrepancy on the use of unclear language in the report but upheld the earlier finding that the officers committed no criminal wrongdoing.

The office's chief civilian director Richard Rosenthal says he received a complaint about the investigation and has now appointed Vancouver-based lawyer Mark Jette to conduct the administrative review.

The BC Civil Liberties Association is among the groups that called for an independent review.

"It's the kind of error that we have always said would really benefit from having an independent review, said executive director Josh Paterson.

"Not just the IIO telling us that they've looked at how they did this case, and made some corrections, but to have someone else come in and say, 'Here on your first case are some of the places that perhaps you could have improved.'"

Greg Matters mother, Lorraine Matters, is pleased there will be a review of of the IIO investigation. 

"I do not have any faith in the system at the moment, and I'm hoping that I'm wrong, that there will be someone who is going to be reviewing every little detail."

The IIO says it is taking this step to ensure the integrity of the investigation. 

Jette will submit his report to the province's deputy attorney general and director of police services.

On mobile? Click here for photos of Greg Matters and the RCMP team involved in the shooting