The assault came to light when a school guard heard student rumors about it, in which the boys grabbed the freshman girl, dragged her into a bathroom and forced her to perform oral sex on three of them as a fourth kept watch.
All four youths face two charges of forced oral copulation and acting in concert to commit a sex crime. One of them is charged with witness-victim intimidation for allegedly threatening the girl if she came forward, which she eventually did. The attack was Dec. 2.
One of the teenagers also is accused in a second incident of accosting a 17-year-old girl on the stairs at Wallenberg during school Dec. 19 and sexually assaulting her, said investigator Sidney Laws.
One of the suspects at San Francisco's Raoul Wallenberg Traditional High School is believed to be a basketball star.
Laws said the suspects' attitude after their arrest stunned her.
"They think they didn't do anything wrong and it's OK for this kind of stuff to happen," Laws said. "They see it as horseplay."
Notable deaths of 2014 [PHOTOS]