BH I wasn't molested, so I can't talk from experience, but all these discussions are good and fine when we are dealing with monetary damages etc, but when you are dealing with a matter of life and death, pikuach nefesh, the Torah clearly states that even when in doubt, you should do whatever is needed to save a life. In this case, if there is a reason to believe someone is molesting kids, and even more so if kids come and say so, then there is a Halachic obligation to report it to the police, and they will do their investigation, and if the guy is innocent - BH, and if he is guilty - at least we prevented him from damaging other people.
That's my NSHO