Coquitlam Mounties are looking for "important" witnesses to a crash earlier in the month involving a motorcyclist.

It happened on Friday, Aug. 3 around 8:45 p.m. when an SUV making a turn onto Emerson Street collided with an eastbound motorcycle that was travelling on Foster Avenue.

Authorities say the 22-year-old motorcyclist was left with "life-altering injuries" and has not been able to speak to officers yet.

Investigators believe a driver in a dark-coloured sedan was in the area at the time of the collision.

"All witnesses are useful, but anyone who was in the dark sedan may have important information and we'd like to speak to them as soon as possible," says Cpl. Michael McLaughlin.

RCMP are also interested in speaking with anyone who may have seen the motorcycle or SUV, or may have dash cam video of either vehicles earlier that evening.

The driver of the SUV remained on scene and is cooperating with RCMP.