The actor was thought to be healthy otherwise, aside from a bout with COVID last year.
Law enforcement sources now tell TMZ they believe Leslie had a heart attack before the accident.
On Monday, "Extra's" Jenn Lahmers was at the scene of the crash and spoke to a security man, who claimed that Jordan was driving very slowly before he clipped a white truck. Cars were reportedly weaving around his BMW and honking just before he crashed into a building.
TMZ notes the medical examiner is investigating, and Leslie’s cause of death has not been announced.