Lambton OPP is asking anyone with dashcam footage of the area at the time of Monday's fatal collision on Highway 402 to contact them.
In a news release issued Tuesday, OPP said they were called to a multiple-vehicle collision in the westbound lanes near Modeland Road at 1:50 p.m.
Lambton EMS, Sarnia Fire and Rescue Services, and Ornge air ambulance also attended.
OPP told Sarnia News Today that five vehicles were directly involved in the collision, three commercial vehicles and two passenger vehicles.
Police said the driver and passenger of one of the involved vehicles were pronounced dead at the scene. Their identities have not been released but police said the deceased were a 61-year-old man and a 54-year-old woman.
Another individual in a separate vehicle sustained serious injuries and was transported to hospital.
The West Region OPP Traffic Incident Management and Enforcement (TIME) team attended the scene to assist with the investigation.
The scene was cleared around 1 a.m. Tuesday and the highway was reopened to traffic.
Those with dashcam footage are asked to call Lambton County OPP at 1-888-310-1122.