According to police, hikers saw what looked like blood splattered on rocks and alerted authorities on Tuesday. Investigators searched the area at night and in the morning.
"We do have a blood trail. However, we found no evidence of any remains whatsoever," said Lt. Mike Rossen of the L.A. County Sheriff's Department. "The shallow grave was processed, and it's just an empty cavernous hole in the ground."
Detectives are treating the area as a crime scene, but they're not sure exactly what they are dealing with.
The blood is being examined to figure out whether it is animal or human. Authorities say they may not get results for days.