Missing woman Mitrice Richarson (pictured above right), who vanished nearly a year ago after a Malibu Sheriff's station released her in the middle of the night, may be alive and living in Las Vegas.

Sheriff's Department spokesman Steve Whitmore says the claim is "not definitive," but L.A. investigators plan to hold a joint press conference with Las Vegas authorities on Thursday to announce a joint search, and to urge her to contact them, according to theLos Angeles Times.

Whitmore stressed that if she came out, she would not be in trouble, nor would she be arrested.

Mitrice's father, Michael Richardson, said that a Sheriff's Department official told him the department had information regarding close to 80 possible sightings of Mitrice in Vegas. 

Whitmore would not confirm that number but he said, "They wouldn't be doing this if they didn't believe they had credible information of her whereabouts. They want to prove or disprove beyond a shadow of a doubt that these sightings are indeed fact or indeed not fact."

Richardson's parents, family, and girlfriend have all fronted efforts to find her since she was last seen leaving the Malibu/Lost Hills Sheriff's Station in the early hours of Sept. 17. She had been arrested for not paying a dinner bill at Geoffrey's Restaurant, where witnesses say she had been acting erratically. A few hours after being released, a nearby Malibu resident made a call to police after seeing her wandering aimlessly and speaking to herself.

Richardson, who was diagnosed with bipolar disorder, was released from the station in the predawn hours in an area she was unfamiliar with, lacking transportation, a cell phone, or money.

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