An unidentified human head was found at a California recycling plant on Wednesday, and police are treating it as a murder case.
Workers at the California Waste Solutions plant in West Oakland found the body part and called authorities.
Cadaver dogs were brought in to search for additional body parts but did not find anything.
They said the skull showed signs of foul play, indicating the person was likely murdered and was also dead for some time.
Authorities do not know the gender of the victim, but are going to use dental records to try and identify the skull.
Police were called to the site on Wednesday morning when workers found the body part in a load of recycling that was dropped off.
They have launched an investigation, which includes attempting to locate where the recycling load was picked up.
The plant accepts all types of materials, including paper, envelopes, file folders, newspaper, magazines, junk mail, cardboard cans, glass, plastic, metal wood and Styrofoam.
They also collect debris, construction and demolition waste, refuse, compost and organic material.
A wide area is covered by the plant, mostly around the Bay Area.