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.