Yes, I thought it was Profazio too. And I thought it was one of those things that was being bandied around "off the record" as such, by the beaming cops who were basking in the glory of having "solv-ed ze crime" (c. Inspector Clouseau) in front of the world's media at that triumphalist press conference.
I don't think that this phrase was necessarily said in front of a microphone as part of the official press conference. Rather, as I say, I think it was being said around the room by Profazio (and maybe other officers) who were pumped full of pride, hubris, excitement and extreme self-importance. Probably someone who was present at the press conference would know for sure.
You are likely correct. This article from November 6th 2007 doesn't mention Profazio at all and uses other words for caso chiuso. I am assuming though that Castellini was at that press conference and heard the words.
http://www.ilsole24ore.com/art/Sole...00000e251029&DocRulesView=Libero&refresh_ce=1