It isn't a chain. The knife, the bra clasp, the interrogation, etc. etc. don't all have to be true, nor do any of them individually have to prove anything beyond reasonable doubt.
Machiavelli has argued this as well, stating it (the Italian system of determining guilt) is similar to a point system and the whole should be judged rather than each individual part. The primary reasoning goes that the likelihood of all of this evidence being wrong is extremely low. Odds are that most of them are true just by the preponderance of the total. My opinion is that a mountain of unproven evidence proves that you have a mountain of unproven evidence.
Using a point system, the only real points scored by the prosecution are the fact that Amanda and Raffaele have not been completely truthful (as I previously stated as the only "solid" evidence) coupled with the fact that they have both been in error or mistaken about some of the times and sequences of events.
The evidence on the knife blade simply proves Sefanoni's desperation to find something tying Amanda to the murder.
The evidence of the bra clasp simply proves Stefanoni's desperation to find something tying Raffaele to the murder.
The evidence of the Luminol prints (with a negative TMB test for blood and the lack of Meredith's DNA in the vast majority of prints) simply proves that it is not known what made those prints, who made them, or when they were made.
The mixed DNA/blood trace in the bathroom simply proves that Amanda lived there and used that bathroom.
The evidence of a staged break-in simply proves the desperation to confirm the initial theory of the police. In my opinion there is as much evidence it was not staged as there is for a staging.
The evidence of Meredith's cell phone activity is stronger evidence of an earlier TOD than later, in my opinion.
The stomach contents argument is also evidence of an earlier TOD.
The computer evidence is a big question mark and may show stronger evidence of an alibi if the court allows retesting. At this point it only shows the lack of confirmation of an alibi in the 9:30-midnight range, not proof that their alibi is false.
Curatolo's testimony is false (see above).
Quintavalles's testimony is false (I have posted on this one numerous times).
Nara testimony proves that she is confused on dates and times and proves nothing, in my opinion.
The knife as a murder weapon defies logic and common sense as well as the forensic evidence that another knife is needed to account for all of the wounds.
The lack of motive, the prosecution's fantasies, and lack of a cohesive theory prove the overall desperation to confirm the early hunch by the authorities.
Manga and pot prove they have much in common with others of their generation.