This is Larry Johnson talking, who's not only a Hillary zealot but is generally unreliable. "21 indictments" against Karl Rove and all that.
File it under "doubtful." I remember all the Magic Bullet scandals that were claimed to be just about to break and take down Clinton. As a rule, rumors about such stuff are just flat-out false. If someone has such a tape, they release it. No one keeps secrets like that.
On the other hand, here's a vid making the rounds of Obama's very own Bosnian Sniper Incident. Not nearly as good as Hilary's, though, and it will have zero impact on the campaign.