Andrea Nichole Palma-Thomas was located in Anaheim Hills on Tuesday. She was taken into custody for outstanding warrants, police said.
The other three women -- Kianna Jackson, Josephine Vargas and Martha Anaya -- remain missing. Investigators say they do not know if the disappearances are related or if the women are victims of foul play.
Jackson, 20, was the first to disappear on Oct. 15. She got off a bus at the Santa Ana terminal and immediately checked into a motel in Costa Mesa, but then disappeared several days later.
Vargas, 34, vanished two weeks after Jackson. Then on Nov. 12, Anaya, 28, disappeared.
Police initially said all three women disappeared along a half-mile stretch of 1st Street between Grand Avenue and the 55 Freeway, an area known for prostitution and drugs, but now they say Jackson has not been connected to the East 1st Street area.
Police say some of the women have substance abuse issues or have been arrested for prostitution in the past.
Palma-Thomas had also been reported missing and was thought to be connected to the other missing women, but detectives now believe there was no connection. Palma-Thomas said she knew she was missing but did not want to be found, police said.
Family members fear that the women may have been kidnapped for human trafficking. They say other women in the area have told them that several suspects have tried to grab them.
Police have entered the women in the National Missing and Unidentified Persons System and have also been checking jails, hospitals and morgues for any signs of them. So far, investigators have found no clues.
The investigation is ongoing. Anyone with information was urged to contact OC Crime Stoppers at (855) 847-6227.