Reyna Marisol Chicas was placed under a 72-hour mandatory hold after it was determined she was not able to care for herself or others, said Los Angeles County Sheriff's Deputy Thomas Kim.
Chicas gave investigators a false name and was rambling during questioning, Kim said. She told deputies she had no children, even though her two kids were with her.
Ending a frantic search, deputies found Chicas the 13 just before noon at Jackie Robinson Park near Palmdale after getting a tip from a local resident, said sheriff's spokesman Steve Whitmore. He said all members are safe.
Officers had been searching a wide swath of Southern California since Saturday after family members found letters saying the group was awaiting an apocalyptic event and would soon see Jesus and their dead relatives in heaven.
The group of El Salvadoran immigrants described as "cult-like" by sheriff's officials, was led by Chicas, a 32-year-old woman from Palmdale in northeast Los Angeles County, sheriff's Captain Mike Parker said.
Members left behind cell phones, identifications, deeds to property, and letters indicating they were awaiting the Rapture. The items came from a purse that a member of the group had left with her husband Saturday and asked him to pray over. He eventually looked inside and he and another member's husband called authorities.
"These letters read like a will and testament. They read like goodbye letters," said Whitmore. "Coupled with the two husbands that come in and tell us 'Our wives are missing, we believe they are under the spell of this lady,"' deputies had no choice but to treat the matter seriously, he said.
Two women from the group called fears for their well-being a misunderstanding.
"That's our husband. When you go somewhere overnight, you don't know what's going to happen to you right?" Alma Miranda Pleitez told KNX radio at the park shortly after she was found. "So you leave your information to your husband."
Another member - Martha Clavel - told the radio station "I guess it was a misunderstanding, and I'm sorry about that." Whitmore said he didn't know if the members had done anything like this before.
Sheriff's officials said there was no criminal investigation planned.
The men told investigators they believe group members had been "brainwashed" by Chicas, and one expressed worries that they might harm themselves, Parker said. One of the children is 3, and the others range from 12 to 17.
When deputies arrived at the park they found the children playing on swings and the adults on a blanket praying out loud in Spanish.
The adults expressed shock at the notion that they might harm themselves, Parker said.
A sheriff's deputy had spoken to members of the group at 3 a.m. Saturday while they were praying in their parked vehicles outside of a Palmdale high school, Parker said.
When the deputy made contact, adults in the group told him they were praying against violence in schools and against sexual immorality, specifically premarital sex.
The 13 adults and children were in three vehicles outside Pete Knight High School, Parker said. The deputy reported everyone appeared safe and he went on his way.
Chicas used to be a member of Iglesia De Cristo Miel, a Christian congregation in Palmdale, but left about two years ago without much explanation, said Pastor Felipe Vides, who said he had spoken with the sheriff's office.
"She appeared normal, calm. We didn't see anything strange," Vides told The Associated Press on Sunday.
The church has about 400 members, mostly immigrants from Latin America, Vides said.
Chicas apparently had formed her own religious group, Parker said. About 12 to 15 people would gather at her home in Palmdale, a high-desert city of 139,000, and one night about a week ago, they didn't leave until 2 a.m., said neighbor Cheri Kofahl.
"We've got a group here that's practicing some orthodox and some unorthodox Christianity," Parker said. "Obviously this falls under the unorthodox."
Others who knew Chicas said she was devout but hardly fanatic in her religious beliefs.
Former neighbor Ricardo Giron told the Los Angeles Times that Chicas became increasingly religious after she separated from her husband four years ago.
But Giron's wife, Jisela, said the church she had attended was a typical Christian congregation and Chicas did not have a leadership role.
The couple said Chicas regularly baby-sat for their children and the two families went on outings together.
"Everywhere she was going, she was taking her kids with her," Giron told the newspaper. "You felt like you could trust her."
About six months ago, the group had planned to head to Vasquez Rocks, a wilderness area near Palmdale, to await a catastrophic earthquake or similar event, but one member of the group revealed details of the trip to relatives, Parker said. The trip was called off and the member kicked out.
Associated Press Writers contributing to this report include Christopher Weber and Andrew Dalton in Los Angeles and Ana Elena Azpurua in New York.