Someone emailed me this thread and asked me to get involved here. There is an organization in LA called Alleinu http://www.aleinu.net, the founder or one of the founders is Mrs. Debbie Fox and she is instrumental in teaching schools and parents how to keep their children safe. Please contact her ASAP for help in regard to this situation.
I agree that if a 15 year old boy is molesting other children something must have happened to him as well and he needs psychological counseling. It would be important to take him out of the main stream yeshiva or at least hire a shadow for him so that he is never alone with anyone. He needs intensive therapy to understand what he is doing and why he is doing it and probably medication to lessen his urges as he goes through therapy. I wouldn’t condemn him off the bat not knowing the particulars but I would say that he cannot be trusted to be on his own and needs 24/7 round the clock supervision.
It is much better for others to think that he has a medical issue and needs a companion because of it, than for people to know that he did this if doctors believe they can work with him and help him if indeed he is a victim himself. The first and most important thing to do is to keep him from harming others and of course himself in the process. So the first and most important thing to do is neutralize the situation by making sure, absolutely sure, that he cannot have access or harm anyone. He should not be allowed total freedom nor total liberties to walk where he chooses, go where he wants, nor do what he wants. He gave up that right by acting on his urges and hurting others. There are always consequences for his actions and the consequences here should be intensive therapy and a shomer.
Is it necessary to publicize who this child is at this point? I cannot give an answer on that especially without an evaluation from a qualified psychiatrist. So I would again advise that you the poster or rather the parents of the abused children contact Debbie Fox and her team to inform them of the situation and let them advise you or even handle it from their end by contacting the parents of the 15 year old boy.
In the event that the parents and the 15 year old abuser do not want to cooperate in getting help, then I would say that you absolutely need to circulate his information and that of his parents so that the entire community knows to be wary of them. But first give the teen a chance to get help because he may very well be as much of a victim as are his own victims, and his parents might not have even known about it.