So close to Halloween, it looked like a ghoulish prank. But it wasn't long after police in California were called to a woman spotted carrying a skull on a stick that officers' faces dropped.

Police found the woman at an abandoned house in Connie Drive, a residential street in Sacramento, at about 1.40pm on Wednesday (19 October).

Carrying the skull upright on a stick, she led officers not to a Halloween party but to decomposed human remains at a nearby homeless encampment.

"She brought the officers to the area where she located the skull," Sacramento police Sgt. Bryce Heinlein told reporters. "When the officers went out there they located a decomposed body.

"It's not something that happens every day and we hope we can get down to the bottom of what caused this person to become deceased."

Homicide detectives joined investigators at the camp, in Crosby Way, for many hours between Wednesday and Thursday to gather the remains and comb the scene for clues.

The body hasn't been officially identified and Sacramento Police Department said the investigation is still ongoing "to determine if foul play was a factor".

A neighbour of the encampment, "Philip", told KTXL News another homeless woman, by the name of Victoria, had lived there for years. He said the body was discovered among some bushes just a few feet from her possessions.

Another neighbour, Warren, said he'd even smelled a revolting stench coming from the area but thought it was a dead cat. "I went to walk back there and thought, Damn! What the hell is that smell? It make me sick to my stomach, so I turned ... and came back here," he said.

The coroner will now seek to determine the sex, ID and cause of death.