You are right, there is no forensic evidence. The 'circumstantial' evidence and the picture that is being built up now by the police is all there is to go on along with testimonies. Some people think that is substantial evidence. Others may never be satisfied that it is. Leave it to the police and the law is or should be all that is necessary now.
Sworn testimony is usually a vital part of any sexual abuse case. Rarely, if ever, are such incidents caught on camera or witnessed by other people. I'm not exactly sure what "proof" people are talking about when they say they are sceptical about such cases.....if we took that to it's logical conclusion, very few sexual abuse cases would ever end up in court.