Two of the girls were 14 and the other was 13. The victim was another 13 year old and the attack happened at school.
Apparently the victim was not seriously injured and did not tell her parents that the attack happened.
After making the video of the attack, the trio placed it on two web-sites. Police in Long Island's Suffolk County were shown the websites and tracked down the girls and the victim. The three girls were arrested on charges of juvenile delinquency and attempted assault.
Police still have not found the camera person. More here. µ