VANCOUVER -- B.C.'s police watchdog is investigating a Coquitlam collision that sent four people to hospital Sunday.

The crash happened on the Highway 1 exit at Brunette Avenue at about 9 a.m. The Independent Investigations Office says it's looking into the incident because an officer was conducting radar speed detection on the highway at the time.

Ron MacDonald, civilian director of the IIO, said the officer with the RCMP Port Mann Traffic Unit observed a female driver in a grey Dodge Charger allegedly speeding, prompting him to attempt a traffic stop.

“The vehicle sped away and took the Brunette exit from the TransCanada Highway and collided with another vehicle at that intersection,” MacDonald said.

He said an SUV carrying a family of five was at the traffic light when the driver of the Charger crashed into it, injuring the three young people inside.

He said the three passengers are under 13 years old and were taken to hospital.

“Their injuries are not as serious as initially believed. They all do have what might be called serious injuries, but they're not life-threatening and they are expected to recover,” MacDonald said.

He said the other driver, a woman in her 30s, was also transported to hospital but had relatively minor injuries.

The IIO is now reviewing to see if the officer’s actions played any role and determine if charges should be recommended.

Investigators with the IIO are piecing together what led up to the moments before the crash.

“There was a point where we believe the officer was trailing the Dodge Charger in his vehicle, However, all the details of that we’re still figuring out, and will be part of our investigation,” MacDonald said.

The on and off ramps, plus the overpass at the Brunette exit, were all closed for several hours on Sunday because of the crash.

The IIO will investigate what role, if any, police action or inaction played in the injuries. Investigators are asking witnesses who saw or recorded the incident to call the IIO witness line at 1-855-446-8477.

Correction:

Authorities initially said six people were sent to hospital Sunday, but the IIO has since confirmed that four people were actually hospitalized.