San Diego police are still investigating the cause of a deadly head-on crash that occurred earlier this week in Oak Park.

On Tuesday, Jose Lerma, 36, was killed when his SUV slammed into a garbage truck on eastbound SR-94 near Federal Boulevard.

Police said oil on the road caused Lerma's SUV to lose control and skid into the garbage truck.

Investigators are looking for the person or persons responsible for illegally dumping the oil on the road.

Anyone with information is asked to call Crime Stoppers at (888)580-8477.