They were confounded by their belief in the burglary first and it drove them to impossible further conclusions. It just couldn't be the simple case it was because if it.
The conclusion about the burglary combined with the later car park kiss and let's not wait for the forensics kind of approach. It's astonishing to me. Even now.
The possibility that the police and prosecutor did believe the burglary was staged and that led to the course of events is could be the reality.
But the other possibility is that the police and prosecutor were corrupt and desiring of the very quickest resolution of the crime for several reasons (not all the same for each individual), such as satisfying political pressure for a quick resolution, gaining professional recognition, misogyny, and obsessions with sexual and "satanic" rituals.
In the latter possibility, the need to attribute the crime to a "convenient suspect", one close to Meredith, would suggest to the police and prosecutor to maintain that the break-in and burglary were staged.
From Sophie Purton's Nov. 3 witness statement, I make the following observations:
The most interesting things about this witness statement from Sophie Purton:
1. The "generals" Giobbi and Profazio, and the "colonel" Napoleoni were present, suggesting the high level of importance that the police gave to this interview.
2. Purton states that Meredith told her Amanda Knox brought men home: "I (Purton) don't know how many".
3. Purton states: I think that, for Amanda, some of these men were only friends, while I think she slept with the one who works in the cyber cafè.
4. Purton states that Meredith smoked pot and Purton thinks Amanda smokes it also.
5. Purton states: I know Hicham knew Meredith because he met her though me, but I don’t know if Amanda knew him.
6. Purton is sworn to secrecy. I suggest this is important; among the witness statements translated so far, I believe only one other witness was sworn to secrecy, Stefano Bonassi, the downstairs neighbor, who had blood stains on his bed. Bonassi was interviewed by Giobbi, Profazio, and Napoleoni and also sworn to secrecy on his second interview, also on Nov. 3.
I believe (based on intuition and my biases) that Purton's statements, shown here as #2, 3, and 5, suggest that the police were aiming their suspicions at Amanda as of Nov. 3, 2007.
I suggest that the police solicited Purton's views on Amanda and on Amanda's relationships to men. The impression I have is that the police were seeking the male partner in the sex crime and murder that they were already considering to attribute to Amanda.
The secrecy imposed on Bonassi I suggest was so that he would not reveal that the downstairs evidence might complicate the police/prosecution theory of a murder by a flat mate and her male accomplice(s).
That imposed on Purton I suggest was to prevent any word of police/prosecution suspicion getting back to Amanda.
Bonassi was interviewed 3 times, Purton 2 times.
ETA:
http://www.amandaknoxcase.com/witness-depositions/