A 42-year-old Chemainus man is dead and a 38-year-old Aldergrove man is in custody after a crash between a motorcycle and a tractor-trailer north of Quesnel early Thursday morning.BC Highway Patrol says the collision happened at 12:34 a.m., when a black Kenworth tractor-trailer struck a black Harley Davidson motorcycle on Hwy. 97 near Naver Creek Rd. The motorcycle rider died at the scene. The driver of the truck was arrested on suspicion of impaired operation of a motor vehicle.Investigators are asking for public assistance to determine what led to the fatal crash.“Police need your help locating more witnesses to this collision, and dash-camera video would be helpful,” said Cpl. Michael McLaughlin with BC Highway Patrol. “The driving behaviour leading up to the collision is very important, and there may even be witnesses who saw concerning behaviour hours before the crash.”Anyone who witnessed the crash or saw either vehicle beforehand is asked to contact BC Highway Patrol – Quesnel at 250-992-9211, quoting file 3304 2025-5987.