A question about sexual abuse and extortion?

My boyfriend's friend claims she was molested by someone who is a friend of the family's. She threatened to go to the police unless he gave her money and has thus far extorted over $50,000 from him in a three year period. The guy who supposedly did it says he didn't do it but can't afford to have her accuse him of it or he'd lose his job. If she's already extorted $50,000 out of him, can a sexual abuse case be thrown away and she be arrested for extortion and coercion? If I have a snapshot of her account and the money in it that doesn't belong to her, can I submit it anonymously? Is this a serious enough claim for the police to even take an anonymous claim seriously?