Sometimes in the examination of the Amanda Knox - Raffaele Sollecito case posters here rightfully examine deeply the minute details of the case. In doing this, we all sometimes neglect that it is difficult to determine the motivations and intentions of the Italian police in attempting to solve the murder/rape of Meredith Kercher so quickly, apparently before significant forensic results had been obtained. This post is intended to give an overview based on my understanding.
I have suggested, based upon the testimony of VQA (= assistant vice commandant, IIUC) Edgardo Giobbi, that there was a search by the police for "suspects of convenience". That is, the police first looked at the persons closest to Meredith in Perugia as potential suspects. This is actually an effective method in many murder investigations, as long as it is followed with open-minded honesty and competence.
The problem in this case is that there was no open-minded honesty or competence. An important element of the crime scene, the apparent break-in through Filomena's window, was quickly and erroneously attributed to staging. Giobbi's testimony provides reasons for this attribution, but none are objectively supported by forensic evidence; except for the reference to glass fragments on top of clothes and lack of glass on the ground (neither of which were objectively documented by photography), the other reasons related to Giobbi's intuition or experience. The relative absence of glass on the ground would actually be consistent with a rock thrown from outside through the window.
While one of the Postal Police reportedly questioned whether there was a burglary, it is plausible (as pointed out recently by Bill Williams) that the PP's statement may have meant he perceived an incomplete burglary.
My inference is that when Giobbi identified Amanda's alibi for the night of the murder as resting only on her being with Raffaele in his apartment, and as he stated weaker than that of the others close to Meredith, and recognizing her lack of a lawyer and relative unworldliness, he fixed on her as a "suspect of convenience". No doubt the obsessions and legal problems of the director of the investigation, PM Giuliano Mignini, and the views (unknown to us) and integrity (later found questionable) of Deputy Police Commissioner Monica Napoleani were important.
But what motivated the police to move so quickly, apparently before the significant forensic results were obtained? I believe it was not merely incompetence. Certainly the anticipated arrival of Amanda's mother on Nov. 6, 2007 could have played a role. But there were significant political and media pressures on the police, as this well-known quotation from the Nov. 6 press conference states:
It was these pressures on the police that motivated their initial misconduct, the procedurally illegal interrogations of Nov. 5/6, 2007, and of course it was the lack of integrity of the police that allowed that misconduct. The interrogation of Amanda Knox included, if one accepts her claims of being threatened and hit, violations of Italian criminal law punishable by imprisonment. The continued police, prosecution, and judicial misconduct after the interrogation were motivated by not merely the desire to save face, but a desire of the judiciary (which includes the police and prosecutors as well as the judges) to defend the police from possible criminal charges. Fortunately, not all the judges have felt that their responsibility to the judicial team outweighed their responsibility to provide some justice in the case. Thus, the Hellmann court provisionally acquitted and the Marasca panel of the CSC has now (March, 2015) finally acquitted Amanda and Raffaele.
ETA: Souce:
http://www.amandaknoxcase.com/
ETA2: Amanda Knox remains convicted of calunnia against Patrick Lumumba. She has lodged a claim against Italy with the ECHR regarding this conviction as a violation of her rights under the Convention.
