MALIBU, Calif. -- Friends and family scoured the Santa Monica Mountains on Saturday for clues to the disappearance of a 19-year-old college student who vanished while heading to a party hosted by a convicted sex offender.

About 100 people searched hillsides and cliff roads for eight hours, looking for traces of Donna Jou.

"I'm hoping to find something, some answer, something that's related to Donna," said her mother, Nili Jou, who believes her daughter is still alive. "It's been six months and I have no idea what happened to my precious baby."

Gloria Allred, an attorney representing the parents, Nili and Reza Jou, said she and other searchers found several blue backpacks of the same color and brand that Jou was carrying but none appeared to belong to Jou after closer examination.

Allred said the group also found jewelry and clothing, all of which they bagged and turned over to police.

"We're just looking for everything and anything that might lead us to Donna," Allred said.

Jou, a San Diego State University biology student, was living with her mother in Rancho Santa Margarita for the summer when she vanished. She was last seen on June 23 on the back of a motorcycle driven by John Steven Burgess and was believed heading to a party he was hosting at his rented house in West Los Angeles.

The two met on the Craigslist Web site.

Burgess had been in the area being searched "and Donna was last seen at a house that's not very far of a drive (away)," said Mike Melson, founder and president of Trinity Search & Recovery, a volunteer group that was helping with the search.

Allred would say only that searchers received a tip that "she might have been taken to this area" but declined to be more specific. The search was to continue Sunday.

Burgess, 35, has not provided information to investigators about Jou's disappearance. His attorney has said he denies any involvement.

Authorities said Burgess remains a person of interest in the case but he has not been charged with a crime.

In 2002, Burgess was convicted of three counts of battery and of performing a lewd act against a child the following year.

He left California shortly after Jou disappeared. He was arrested in July in Jacksonville, Fla., and returned to California to face a charge of failing to register as a sex offender while living in Los Angeles.

In October, Burgess was sentenced to three years in prison after pleading no contest to failing to register and to another charge of failing to file a change of address.