Two special needs teenage twins have been missing from their Southern California home since Sunday, and their parents fear their daughters met someone on the Internet and could be in danger.

Mary and Morgan Corrodi, 16, were last seen outside their Malibu home getting into a car occupied by two women. Jack Corrodi said his daughters, who have IQs of 70 and attend special education classes at Malibu High School, recently spent "many hours" on the Internet and received multiple calls from unknown persons.

"[A neighbor] saw the girls standing there, just kind of hanging around like they were waiting for somebody, and a few minutes later, a small car pulled up and the twins got in the back seat," Corrodi told FOXNews.com. "And then they drove away and we haven't heard from them since."

Corrodi said the girls are "very slow mentally" but appear to be much older than 16. He's fearful someone they met online may take advantage of their disabilities.

"It's possible, that's what I'm afraid of," he said. "They look, up close, like they're 22, and mentally, they're 10 or 11. They're very slow mentally. They each have dolls and they still play with them and yet their interest is to meet boys."

Malibu Police Department Lt. Richard Erickson said the teens have currently been classified as runaways.

"Mr. Corrodi indicated that the girls had run away from home in the past, but had always returned that same day," Erickson's police report reads. "These 'run away' instances were never reported to law enforcement."

Erickson said Thursday that police aren't even sure what the girls' mental capacity is.

"The exact status of their mental health is a little convoluted right now," he told FOX News. "We don't know what their mental state is."

For now, foul play has been ruled out, according to Erickson.

"At this time, that's not in the picture at all," he said.

Meanwhile, the girls' mother, Kathryn Corrodi, told MyFOXLA.com that she fears the worst.

"I'm afraid," she said. "I don't know if someone is holding them because I think they'd be home if they could get home."

Jack Corrodi said he was unaware that the girls had at least seven MySpace accounts, including one most recently accessed on Sunday.

"They would look up a few things on the computer, usually with the argument that it was something for school," he told FOXNews.com. "We were unaware it might lead to this."

Click here to read more on this story from MyFOXLA.com.