The Independent Investigations Office is investigating after a "distraught" man died in Port Coquitlam Sunday night.

Coquitlam RCMP were called to a residence in the 2100-block of Audrey Drive shortly after 7 p.m. Mounties said initial reports suggested the man was firing shots into the air outside the home.

Witnesses saw heavily armed officers descend on the neighbourhood, guns drawn. One neighbour said members of the Emergency Response Team ran though homes in the area.

Residents reported hearing gunshots soon after, including one that a witness believes struck a home down the street.

Police said they found the man outside the home. A standoff took place, with shots fired by both the man and police, the IIO said.

Half an hour later, the man was dead at the scene of what police said appeared to be a self-inflicted gunshot wound.

But the IIO said it was investigating whether his injuries were caused by his own actions or by responding officers. Investigators will also look at whether Mounties' actions were lawful and reasonable.

The man has not yet been publicly identified.

Members of the police watchdog gathered evidence, and are conducting interviews with Mounties and witnesses.

Those who witnessed the shooting incident are asked to contact the organization at 1-855-446-8477, even if they've already spoken with the RCMP.

With a report from CTV Vancouver's Michele Brunoro