Can I sue for being falsely accused of molesting a child?

State laws vary significantly, especially your state. However, many states protect accusers acting in good faith. Contact a lawyer in your state to discuss your potential claim.

I agree with Mr. Lassen, that it may not be a clear case. If the allegations are leveled within the confines of a court case, there may be immunities that apply. Also, given the awareness (rightfully so) of child abuse, there may be shield laws that protect those who report suspected abuse. Further still, if the "report" is couched in the form of an opinion, there may be additional protections for the accuser there. Generally speaking, defamation claims require a knowingly false statement "published" either orally or in written form, that causes damage. You should present all the facts to a local PI lawyer to assess your options.