The gang rape and beating of a 15-year-old girl on school grounds after her homecoming dance was horrific enough. But even more shocking, police say, was that up to two dozen people watched and did nothing to stop it. 
 
 The picnic area at Richmond High School in Richmond, Calif. where police said a 15-year-old girl was allegedly raped and beaten Saturday night, Oct. 24, 2009, is pictured on Tuesday, Oct. 27, 2009. According... (Associated Press) 
 
 CORRECTS DAY OF DANCE TO SATURDAY Police cars sit parked outside Richmond High School on Tuesday, Oct. 27, 2009, in Richmond, Calif. Authorities are investigating the rape and beating of a 15-year-old... (Associated Press) 
 
 CORRECTS DAY OF DANCE TO SATURDAY -- Sergeant Eddie Russell escorts a possible witness to his patrol car outside Richmond High School on Tuesday, Oct. 27, 2009, in Richmond, Calif. A 15-year-old girl... (Associated Press) 
 
 This undated booking photo provided by the Richmond Police Department shows Manuel Ortega. Ortega, 19, is charged with rape, robbery and kidnapping in connection with the assault of a 15-year-old girl... (Associated Press) 
 
 The picnic area at Richmond High School in Richmond, Calif. where police said a 15-year-old girl was allegedly raped and beaten Saturday night, Oct. 24, 2009, is pictured on Tuesday, Oct. 27, 2009. According... (Associated Press) 
 
 The attack over the weekend rattled this crime-ridden city of 120,000 in the San Francisco Bay area, where one police official called it one of the most heinous crimes he has ever seen. Some students have already left the school in response to the attack. 
 
 "It's not safe there at all," said 16-year-old Jennie Steinberg, whose mother let her transfer out of the school Tuesday. "I'm not going back." 
 
 The victim, a sophomore, had left the dance and was drinking alcohol in a school courtyard with a group when she was attacked, police said. 
 
 Two suspects were in custody Monday, but police said as many as seven ranging in age from 15 to mid-20s attacked the girl for more than two hours at a dimly lit area near benches Saturday night. As many as two-dozen people saw the rape without notifying police. 
 
 Officers found the girl semiconscious and naked from the waist down near a picnic table. She remains hospitalized with non-life threatening injuries. 
 
 "This was a barbaric act. I still cannot get my head around the fact that numerous people either watched, walked away or participated in her assault," Lt. Mark Gagan said Tuesday. "It's one of the most disturbing crimes in my 15 years as a police officer." 
 
 Gagan would not comment on rumors that observers took video of the attack on cell phones and may have posted it online. 
 
 Manuel Ortega, a 19-year-old former student, was arrested after trying to flee the scene. He is being held on $800,000 bail for investigation of rape and robbery. Attempts to reach Ortega at the jail Tuesday were unsuccessful. 
 
 A 15-year-old student also was booked late Monday on one count of sexual assault, Gagan said. 
 
 Late Tuesday, SWAT teams were preparing to make more arrests as police are also offering a $20,000 reward they hope will bring more people forward with any information. 
 
 Even though he said as many as two-dozen people were witnesses, Gagan said officials are still trying to determine the exact number of people involved. 
 
 "I'm confident that the list will expand and at the end of our investigation we will get a clear indication of who was there and who did what," Gagan said. 
 
 The attack occurred in a city that has dealt with its share of vicious crimes in recent years, and the school recently approved surveillance cameras after a series of violent crimes. In one case a few years back, a student was shot outside the school, ran inside and died in the then-principal's hands, said Marin Trujillo, a spokesman for the West Contra Costa Unified School District. 
 
 Richmond is an industrialized conclave near the San Francisco Bay that is known as one of the nation's most dangerous cities. In 2007, Richmond had 47 homicides, and the murder rate led the state for cities with populations of 100,000 or more, surpassing Los Angeles and Oakland. 
 
 That number dropped to 27 in 2008 but has spiked to 44 killings so far this year, amid drug dealing and gang activity that has engulfed the town, Gagan said. 
 
 Gagan said the girl left the dance and was walking to meet her father for a ride home when a classmate invited her to join a group drinking in the courtyard. The girl had consumed a large amount of alcohol by the time the assault began, police said. Gagan said the girl's father tried to call her cell phone, but no one answered. 
 
 Gagan said police received a tip about a possible assault on campus from a young woman who heard two males bragging about it. She was found nearly an hour after the dance, which more than 400 people attended, had ended. ||||| One of the suspects, a 21-year-old Richmond man whose name was not released, was arrested Tuesday night on suspicion of sexual assault and rape, said police Lt. Mark Gagan. 
 
 The other suspect is a 15-year-old boy who attends the school and knew the victim. The youth was arrested Monday and booked on suspicion of sexual assault at Contra Costa County Juvenile Hall in Martinez. His name was withheld because he is a minor. 
 
 The first suspect arrested, Manuel Ortega, 19, who dropped out of Richmond High in 2007, was arrested as he ran from the scene of the attack at the school about midnight Saturday, police said. He was booked on suspicion of rape, kidnapping and robbery, and could be formally charged today. 
 
 Police initially said about six young men were involved in the attack. But investigators said Tuesday that they now believe that as many as 10 assailants, ranging in age from 15 to their early 20s, committed a "slew of crimes" against the girl - including raping her and stealing her jewelry. 
 
 The men laughed and took photos as they took turns assaulting the girl, police said. 
 
 Police expect to make more arrests, Detective Ken Greco said Tuesday. Authorities are offering a $20,000 reward for information leading to the conviction of any of the assailants. 
 
 Officers passed out flyers in the area of the campus Tuesday and served search warrants at undisclosed locations. 
 
 Greco said Ortega and the arrested teenager have shown no remorse during police interviews. He called the incident "disgusting" and "a sad state of affairs." 
 
 "This is the worst thing I've heard of," said Greco, who has been in law enforcement for 29 years. "It just shocked the conscience of responding officers." 
 
 The girl knew at least one of the assailants, the 15-year-old boy, investigators said. 
 
 The attack began when someone in the group invited the girl to join in a drinking session after she left Richmond High's homecoming dance early about 9:30 p.m. Saturday, police said. 
 
 The girl quickly became drunk, and the attack began. During the next two hours, as many as two dozen people may have witnessed the rapes or been aware of what was happening, but didn't report it, police said. 
 
 Officers were finally alerted by a woman "who was several blocks away who heard people discussing what was occurring" at the school on 23rd Street and called police, police Lt. Mark Gagan said. 
 
 Officers found the girl semiconscious beneath a picnic table. She was airlifted to a hospital. 
 
 The attack has raised questions about campus security. Richmond High has surveillance cameras, but none is working, school officials said. They said a new system should be in place in the next few months. 
 
 Four police officers and several school security staffers were on hand at the homecoming dance. But two of the staffers, known as site supervisors, left about 9 p.m. because of a "prior commitment," said Marin Trujillo, spokesman for the West Contra Costa Unified School District. 
 
 Police also believed they had enough officers on hand to provide security, Trujillo said. 
 
 This article appeared on page A - 10 of the San Francisco Chronicle
– San Francisco-area cops have arrested three more young men in the savage gang rape, beating, and robbery of a 15-year-old girl outside her homecoming dance while dozens more watched. Five youths are being held, ranging from a 15-year-old boy who knew the victim to a 21-year-old. The girl was drinking outside the dance Saturday night, reports the San Francisco Chronicle, and the group turned on her when she became drunk. Charges are expected today. "This was a barbaric act. I still cannot get my head around the fact that numerous people either watched, walked away or participated in her assault," a Richmond cop tells the AP. "It's one of the most disturbing crimes in my 15 years as a police officer." Some students began transferring out of the school. "It's not safe there at all," said a 16-year-old girl. "I'm not going back."