FULLERTON, Calif. (AP) — Police are investigating after a body wrapped in plastic was found inside the cargo hold of a rental truck that was abandoned in Southern California, officials said Thursday.

Staff at the U-Haul Moving and Storage facility storage facility in Fullerton found the body Wednesday while conducting inventory on the truck, the Orange County Register reported.

The truck had been rented in nearby Anaheim and was found abandoned in that city after the rental agreement expired. It was towed by a third-party company to the Fullerton facility, according to the Register.

Investigators were working to determine who the person was and a cause of death, said Anaheim Police Sgt. Shane Carringer.

“Regardless of whether this was a homicide, something happened here that we need to get to the bottom of,” Carringer told the newspaper.

A strong odor of decomposition hung in the air at the storage facility as police searched for clues late Wednesday, he said.