Sidney is not on her own with this. Sidney and Rudy are the public face of one of the legal teams. Sidney has stated in several appearances that she has a team of lawyers and others working on this. She will not disclose who they are because some have already received death threats. As for the FBI? I hope they are off chasing jaywalkers somewhere. I don't want anyone in the FBI or DOJ touching this. The FBI needs to be completely dismantled and DOJ significantly downsized, err, rightsized.
however, I am guessing that once court documents are generated the investigation and accusations become REAL and hopefully, some good honest smidgen of fibbers and DOJ will enjoin...