There is no more proof for a drug fueled sex party, whatever that is, than there is for a satanic rite.
I really don't understand why it is so important as whether Mignini did or did not at some point use the precise terms satanic, rite, or satanic rite.
I agree, Grinder. When I asked Machiavelli, he said that Mignini wants people to stop claiming that he ever said Satan or the devil simply because it isn't true. I think they may be right that there is no documentation of Mignini saying those specific words with regard to this case.
There also may be truth to what Machiavelli claims about Mignini referring to "themes," keeping in mind, as Diocletus pointed out with his post about bobbing for apples, Halloween can mean different things to different people. Apparently Mignini referred to the ancient Celtic celebration of Samhain, which traditionally marked the end of summer and has nothing to do with the way some people celebrate Halloween in some countries today.
That's the source of the problem, I think. When Mignini said Halloween (which he did say), the English reporters concluded he was referring to the occult. In the first weeks after the murder, many papers printed the pictures of Meredith dressed as a vampire, with blood dripping down her chin. (The blood was removed from those pictures later.) That sort of thing is connected with Halloween in our minds, but it may not have been connected with Halloween in Mignini's mind.
The question remains why he did not raise a stink about this five+ years ago.
The more important issue is the concept of the three people he believes murdered Meredith getting together for the crime or just getting together.
There is no evidence that the three were ever together before they brought Rudy into the court room, as Raf pointed out at the time.
Arguing over the exact terms used seems hugely secondary to showing that they ever were together. Where is the video the police collected showing them walking around that evening and night. It is impossible to believe that the three were able to avoid being captured on video during the day of the first.
As you correctly state, there is no more evidence for a drug-fueled sex party or for anything in Claudia Matteini's report than there is for a Satanic rite. Personally, I am very interested in finding out more about this file they kept on Amanda's "psychology," indicating she was sexually attracted to Meredith. This is another proposition they have no evidence of, but it appears to have fueled the accusations, as well as Machiavelli's (and probably Mignini's) belief in guilt.