The 24-year-old college graduate has been missing for more than a week.
On Sep. 16 she ate dinner at Geoffrey's restaurant in Malibu.
When she didn't have enough money to pay the her bill she was arrested and taken to the Lost Hills sheriff's station where she was also booked for possessing a small amount of marijuana.
Richardson disappeared after being released from jail late that night. She hasn't been heard from since.
Her family members say her behavior was very unusual. They believe she may be emotionally distressed.
"She absolutely was not herself," said Cherie Howard, Richardson's cousin. "We don't know the person that is in that booking report."
The police and sheriff's department are conducting an extensive search on Saturday combing a more than 60 square mile area between Malibu and Lost Hills.
Dogs, searchers on horseback, helicopters and rescuers on foot made their way through the rugged terrain.
"This is not just a one shot deal," said Steve Whitmore from the Los Angeles County Sheriff's Department. "This has been going on since the missing report and this will continue until she is found and we hope and pray unharmed."
Authorities are also checking tips of possible sightings of Mitrice in West Hollywood and Malibu.