First, there is no reason to take away the knife and the bra clasp, and second, the rest of the evidence is the best possible solid set of circumstantial evidence, the best kind of evidence you can have in a trial and absolutely enough to convict.
Of course there is a reason to take away the knife and the bra clasp. Just because you are unwilling to acknowledge that demonstrates a bizarre sense of reality. In fact, you can pretty much be assured that both would be found non- admissible in a US Court. There is little reason to believe that Stefanoni's results are the result of Amanda and Raffaele being involved in the murder.
As for the rest being a "solid set" of circumstantial evidence is also demonstrates that sense of bizarre. There is nothing solid about them.
The time of death is almost certainly before 10 PM and probably before 9:15. The status of digestion points to that.
The prosecution witnesses do not connect the dots, came forward far too late, and our far more likely to be attention seekers than anything else.
There is NO evidence of the supposed break in being staged.
There is NO logic to Amanda and Raffaele "hanging around" the Piazza during that evening.
There is logic to either Amanda or Raffaele wanting to kill Meredith.
There is NO connection to Rudy. There is little reason for them to help Rudy kill Meredith or cover it up for Rudy.
There are a lot footprints of Rudy in Meredith's blood, fingerprints of Rudy and multiple deposits of Rudy's DNA including inside Meredith and no known reason for Rudy even being with Meredith or being inside the upper part of the cottage. Yet mysteriously, none of this was found for either Amanda or Raffaele.
The Knife taken from Raffaele's is DOWNRIGHT ABSURD. The logic of Amanda carrying this knife back and forth from the flat to the cottage and then back to the flat is not just absurd. IT IS STUPID. It doesn't match the wounds on Meredith and it definitely doesn't match the bloody stain on the sheet.
There is no reason to believe that the Luminol footprint that Stefanoni found to believe that they were blood because of the TMB tests and lack of confirmatory tests. The bathmat footprint doesn't exclude Raffaele as a possible match, but it also doesn't exclude Rudy and therefore it's value is limited to exclusion purposes.
If this is a set of circumstance that Italy believe is solid, I'm confident that it has a significant number of innocent people behind bars.