As many as a dozen people may have witnessed the brutal gang rape and beating of a 15-year-old girl after her homecoming dance — and the attack may have been caught on cell phone video, police said.

Two suspects were in custody late Monday, but police said as many as five other men attacked the girl over a two-hour period Friday night outside Richmond High School, in Richmond, Calif.

"She was raped, beaten, robbed and dehumanized by several suspects who were obviously OK enough with it to behave that way in each other's presence," Richmond Police Lt. Mark Gagan said. "What makes it even more disturbing is the presence of others. People came by, saw what was happening and failed to report it."

More coverage at KTVU.com.

The victim remained hospitalized with non-life-threatening injuries.

Manuel Ortega, 19, was arrested at the scene and was being held on $800,000 bail for investigation of rape and robbery. He is not a student at the school. Richmond police Sgt. David Harris said he did not know if Ortega had an attorney.

A 15-year-old student also was booked late Monday on one count of sexual assault, Gagan said.

Police are appalled by the horrific nature of the attack.

“I remember thinking that it's like something out of a Hollywood movie,” said Gagan. “It's so extremely vicious and absolutely unnecessary.”

The victim left the high school homecoming dance about 9:30 p.m. Friday and was heading to meet her father for a ride home when a classmate she knows invited her to join a group drinking in the courtyard.

Shortly afterwards, police said, the 15-year-old girl was robbed, beaten and gang-raped for more than two hours. Police theorize the attack was not only watched by up to 12 others but may have been videotaped with cell phone cameras, according to KTVU.com.

The victim had consumed a large amount of alcohol by the time the assault began, police said. Officers came to the scene after getting a call about a possible attack on the high school's campus. They found the teen semi-conscious near a picnic table.

Marin Trujillo, a spokesman for the West Contra Costa Unified School District, said there were four police officers and three school administrators monitoring the dance, but the assault happened away from the gym.

The Associated Press contributed to this report.