They left with 44-year-old religious cult leader Kim Miller.
"When he opens his mouth, it's God speaking, literally. That's what his followers believe," says cult expert Bill Honsberger.
"He believes the world is about to end by December, 1999 roughly, it's all supposed to be wrapping up," Honsberger continues.
Police say it was late in September when Miller and his followers vanished from Denver. Miller had predicted a date when Denver was to be ground zero for a doomsday disaster. It was a disaster that never came. Miller was also $600,000 in debt, and some believe that's the reason he got out of town.
Denver police officer Mark Roggeman says Miller's obsession with Bible passages of an impending apocalypse stirs fears the cult has a suicide pact.
"He could cause them to do a lot of things," says Roggeman.
The mass destruction by Hurricane Andrew, the Jerrell, Texas tornado that killed 27, and the death of Princess Diana were signals, Kim Miller said, that the end was near.
"She felt her life was in danger and said come get me," remembers John Weaver.
Weaver's daughter Nikki was in the cult with her mother for 10 years, but he got her out after an e-mail she sent scared him.
"Her mother became increasingly violent, and Kim had threatened her life if she revealed any of the information that he was teaching to me," says Weaver.
Miller is not officially wanted by police, however. He's technically done nothing wrong.
But in the Colorado mountain town of Pagosa Springs, the mystery of the missing is deep, as four families have disappeared.
"They would never commit suicide or some mass suicide, or go out and kill other people," says Vanessa Griego, whose father and seven other family members are gone. She can only hope they're safe. "Nobody knows and that's what's scary."
Amy Matthews says her ex-husband Kevin Kaywood was brainwashed by Miller.
"He left his family, and he's gone because Kim Miller said so," says Matthews.
But families have vanished, students are missing, and the few who might know where they've gone and why, are keeping their secret.