That very nasty pope may have been Benedict IX. I distinctly remember watching on a TV documentary of some kind, the fact (or documented allegation, perhaps) that one pope or another hosted orgies even in the Vatican, and that he or another even allowed a witches' sabbath or pig sacrifice or something of this sort.
I've been searching Web sites about this to serve your request, but have found them skirting the issue on just how untoward Benedict IX was. Apparently there were others that allowed pagan sacrifices of one kind or another, in whatever proximity to halls of worship.
Oh, you saw a TV documentary. Well, many TV documentaries try to say that Christianity is a hoax. Do you buy those hook, line and sinker too?
Now, when you get your evidence and documentation from a reliable source, get back with me as I said so we can discuss it. Until then, signing off on this!