BBM - I think Otto makes a lot of sense, and I believe it's only incredible and leaves one speechless, if one is totally sold on the lone wolf theory.
Recall that when the murder scene was originally discovered, Batistelli of the Postal Police immediately said that he felt the point of entry had been staged, introducing the idea of the "inside job".
Adding to this , Napoleoni and Mignini felt the locked door and the duvet indicated the presence of a female, and that the idea of a staged burglary might point to the boys downstairs (remember that Rudy often brought them pot, and stayed for the party).
Ergo, when Guede's presence was discovered and Lumumba let go, it wasn't as though the investigators skipped the idea of the lone wolf "to save face". They hadn't believed in a lone wolf in the first place.
That's true that the investigators married to their theory before they had any solid evidence. it's true they suspected Amanda from the very beginning.
When the forensic results came, pointing to a person they never considered and more importantly, there were no forensic evidence at all of Amanda's presence in the room, it was time to reconsider the original theory.
This didn't happen and we see such pattern in many miscarriages of justice. Case of David Camm has many eerie similarities. They targeted the wrong person, close to the victims, they ignored evidence pointing to someone else, when it was no way out because the real killer, Boney, had been found, they said he worked 'in concert' with Camm.