AUSTIN, Texas — Police said Monday they are still investigating the weekend motorcycle crash that killed former Bears running back and Cedric Benson and a woman passenger.

According to police, witnesses said Benson was driving his BMW motorcycle at a high rate of speed through a curving, hilly section of the city Saturday night when he collided with a van that was attempting a left turn.

Police said a passenger in the van and a bystander attempted to help Benson, 36, and his passenger, 27-year-old Aamna Najam. Both died at the scene.

Police said the van driver is cooperating with the investigation. No charges have been filed.

Benson is the second-leading rusher in University of Texas history with 5,540 yards. He was drafted No. 4 overall by Chicagoin 2005 and played eight seasons in the NFL with the Bears, the Cincinnati Bengals and Green Bay Packers.