VANCOUVER -- B.C.'s police watchdog is investigating following a death at a Vancouver Tim Hortons location.

The Independent Investigations Office of B.C. has confirmed the investigation to CTV News, and said in a news release it's seeking witnesses to the incident.

It occurred at the restaurant located at Terminal Avenue and Main Street Thursday afternoon.

The IIO said its investigators were told a man went into the washroom at the Tim Hortons at about 4:15 p.m.

"When the man did not exit after some time, employees at the restaurant called police for assistance."

Vancouver police say they were called to the Tim Hortons at around 6 p.m.

Staff members were trying to close down the dining area, and had asked police to remove him, police said.

When the man came out, Const. Tania Visintin said in an email to CTV News, he was "agitated and aggressive, which resulted in a physical altercation."

The Vancouver Police Department has not provided information on what the altercation entailed, but said the man went into "medical distress."

The IIO said there was some type of struggle, but no further details were given.

Paramedics were called, but the man died at the scene.

IIO investigators are asking anyone who saw, heard or recorded the incident to contact them at 1-855-446-8477. Tips can also be passed on through a contact form on the agency's website.

The IIO is called to investigate all officer-involved incidents that result in serious harm or death, regardless of whether there are allegations of wrongdoing.