The suspect was expected to appear in court Tuesday afternoon.
"Mary" just turned 19, but her parents say she has the mental capacity of a 5-year-old. The family's identities are being protected.
"She said, 'I told him I wanted to leave but he wouldn't let me.' And that made her very, very upset," said "Julie," Mary's mother.
Authorities allege Mary was sexually assaulted Friday afternoon. Her alleged attacker is Raul Barrientos, a 22-year-old from Anaheim. Police suspect he forced Mary into a stall in the men's restroom at the School of Continuing Education in Fullerton, then sexually assaulted her over and over again as she cried.
"She's very frail," said Julie. "So even if she had tried to fight back, I don't think it would make any kind of an impact."
Julie says Mary loves sports but must wear leg braces. Her body is weak due to a form of muscular dystrophy.
"He's a predator and he took advantage of my daughter," said "Joe," Mary's father.
Barrientos allegedly left Mary in the restroom. Campus security found him shortly after. They had already received a report from another woman who identified Barrientos as the man who earlier had approached her.
"I'm pissed off. I'm just extremely mad. How can he go in her school, or any school and harass the kids and assault them," said Julie.
"The public has access to the campus at any time, and so it's possible for any citizen to be on campus," said Christine Terry, provost of the School of Continuing Education. "We feel that our system really worked rather well. As you know, the suspect has been apprehended. He was apprehended very quickly."
Barrientos pleaded guilty to failure to obey direction to leave campus. Nine days later he was arrested, accused of attacking Mary.
Barrientos remains in custody facing up to 150 years to life in prison if convicted.
Police are concerned there may be other victims. If you have information related to the case or the suspect, contact Fullerton Police at (714) 738-6715.