A discarded Halloween prop prompted a death investigation that lasted about three and half hours Tuesday until police realized the skull was only plastic.

Deputy Police Chief Aric Wheeler said police were called to the corner of Hopewell and Sixth streets, where a woman walking her dog said she found a human skull in a vacant lot. The call came just after 4 p.m., and it grew dark as police began to investigate. Police treated the area as a crime scene and gingerly roped it off.

They did not touch or move the skull, but a crime-scene technician took photos of it and sent them to The University of New Mexico to be analyzed by anthropologists. Two of the scientists who first looked at the photos told police they were dealing with human remains, but later, a supervisor who looked at the photos said the skull was not real. The anthropologist realized the cracks the manufacturer put on the top of the skull were not as they would appear on a real human skull, Wheeler said.

"It was legitimate looking colorwise," Wheeler said. "We thought we were dealing with a smaller person."

Wheeler said police were treating the scene carefully because the prop was the size of a child's skull. It reportedly had three teeth remaining in its mouth.

Rita Younis said her neighbor found the fake skull, and both women thought it could be real because there was a lot of crime in their neighborhood. Younis did not see the skull, but when she got home, she said, the area was swarming with cops.

"When I got home, I saw all this crime scene tape," she said. "(The area) was roped off, and the crime scene investigators were here. It was a big scene."

Police protocol for dealing with crime scenes prevents investigators from disturbing remains so they were not able to touch the fake skull to determine it was plastic, Wheeler said. He said police will enter the skull into their evidence locker and label it as "found property."

Contact Natalie Storey at 986-3026 or nstorey@sfnewmexican.com.