From an interview of Douglas Preston by Candace Dempsey
http://blog.seattlepi.com/dempsey/archives/131443.asp
My co-writer Spezi and I believe the Monster of span Florence is a lone psychopath. He killed seven couples, fourteen people. He mutilated the women and cut off their sex organs. Really horrifying. A psychological profile prepared by the American FBI of the Monster stated that he is a lone killer. All the Italian forensic psychologists stated he was a lone killer. And all the evidence gathered at the crime scenes pointed to a single perpetrator. But this is too simple for Mignini. He believes the Monster killings were the work not of a lone killer but a satanic sect dating back to the Middle Ages. His theory, based on nonexistent evidence, supposition and conspiracy logic, was that this sect was operating in high places in government and they needed female body parts to perform Black Masses…
In the Monster case, prosecutors leaked evidence to the papers that turned out to be false. One of the cops working closely with Mignini on the Monster case was actually indicted for falsifying the tape of an interrogation…
You have no idea what it is like to be interrogated. It is a frightening experience. It is easy to break you down. Mignini interrogated me for two hours, demanding I confess to a crime I did not commit, and it was terrifying. He is a powerful interrogator. I could imagine what would happen to a 20-year-old who has been pressured for 14 hours. She could break down and say things, anything, just to stop the interrogation. They really browbeat you.