The California Highway Patrol is asking for help finding additional witnesses to the crash Sunday east of Mendota on Highway 180 in which four people were killed.
Rien Ban, 43, faces four charges of vehicular manslaughter after the head-on collision east of Sonoma Avenue.
The collision involved a Mercedes SUV that Ban was driving and a KIA sedan that was westbound on 180. In particular, the CHP is seeking anyone who might have seen the Mercedes prior to the crash.
Anyone with information is asked to call the CHP at (559) 441-5400.