Police say speed and alcohol may have contributed to a fatal crash that closed the southbound lanes of Vancouver's Granville Bridge early Thursday morning.

The driver of a Honda was killed when his car was apparently rear-ended by a Mercedes around 4 a.m. PT.

The Honda was so badly damaged that firefighters said the car would likely have to be moved to another location to remove the man's body.

The driver of the Mercedes was seen taking a police breathalyzer test at the scene following the crash. Sgt. Brian Montague said he was later detained by police, questioned and released.

Montague said the driver is cooperating with the investigation and it was too early to say if charges would be laid.

Police are also looking for a possible witness, who may have driven off after the crash.

The southbound lanes are expected to remain closed while police conduct their investigation, but Montague said they should reopen in time for the afternoon rush hour.