A man called 911 saying he was chasing someone who stole his pickup truck.
San Bernardino police caught up with the truck and tried to pull the driver over, but he sped away.
Officers backed off the chase when the driver went the wrong way on the northbound 215 Freeway.
The driver then struck a motorist head-on. The victim, identified as Mark Offeney, 57, from Nuevo, Calif., died at the scene.
The suspect was described as a Hispanic male in his 20s, 5 feet 6 inches tall with a shaved head. He was last seen wearing denim jeans, a white t-shirt and possibly a beige sweater.
Anyone with information was asked to call San Bernardino police at (909) 384-5742.