"They left behind a significant amount of personal belongings and written notes," sheriff's spokesman Steve Whitmore told members of the media.
However, officials said there is no evidence they are planning to commit group suicide.
The group, comprised of El Salvadoran immigrants, was reportedly last seen about 1 a.m. Saturday at a prayer meeting in Palmdale.
Sheriff's Cpt. Mike Parker said the husbands of two of the missing adults from the group were asked to keep a purse, and inside it found identification, personal papers and letters suggesting the group was awaiting the end of the world.
"Essentially, (the notes said) we're going to go visit Jesus," Whitmore said. "We're going to visit our deceased relatives. They said goodby to their living relatives. They indicated they were going to the next life, if you will. I'm not quoting exactly, I'm paraphrasing of course, but that's essentially what they said."
Officials said the group's leader, Reyna Chicas of Palmdale, is among the missing. Other adults missing include three women who are sisters.
The children, six boys and two girls, range from 3 to 17 years old.
According to an emergency bulletin put out by the governor's office, in addition to Chicas, the missing include:
No information was provided on the 14th person.
Authorities are searching for three vehicles: a silver Toyota Tundra pickup, a 1995 Mercury Villager with a California license plate SNFX290 and a 2004 white Nissan Quest with a California license plate 6LJF396.
The group had been members of a mainstream Christian church, Parker said. Members expressed concern to their families about their unorthodox beliefs.
"It is an offshoot of a religious group, but not affiliated with anybody," Whitmore said. "It's a group of religious beliefs in and of itself."
The group had planned on going to a wilderness area near Palmdale to await a similar event earlier this year. One member of the group told a family member the details of the trip, and it was called off.
"That person was ostracized from the group and kicked out," Parker said.
The Associated Press contributed to this report.
