Investigators said a skull found in a Hollywood lake by a teenager and a friend is human.

A 16-year-old Boy Scout said his mother forbids him to swim in Oak Lake near 56th Avenue and Douglas Street, but he said he thought if he cleaned it up, doing a good deed, she would change her mind.

He and a friend were cleaning up the lake at about 5:30 p.m. Saturday when they found the skull in the bottom of a clay pot in an overturned shopping cart about 10 feet from the shore.

"I know this lake. I want the kids to stay out of this lake," said the 16-year-old's mother, Brandy Fischer. "This lake is dangerous. It's toxic. I told them to stay out of the lake. My son, being the boy he is, wanted to clean out the lake, thinking he can have Mom (let him) swim in it now. No -- he brought this skull home, and we called the cops, and that was it. It was nasty."

The Broward medical examiner determined the skull is that of a human being, Hollywood police said.

Police divers were at the lake Monday morning, concentrating on the lake's floor. A tow truck arrived to haul something out of the lake, police said.

The medical examiner has not yet determined the gender, age or race of the person whose skull was found in the lake. A forensic anthropologist has been called in to help in the investigation.