Long time lurker, first time poster (not even sure I posted back when this was JREF).
To touch on an older topic of discussion regarding luminol and whether or not confirmatory testing is needed:
-correct me if i'm wrong, but machiavelli was arguing luminol is better at determining blood because it's more sensitive than confirmatory tests (although much less specific)
-machiavelli was arguing luminol reactions in the knox case were proof of blood in instances where no confirmatory tests were done (or if they were done, results were not revealed). Maybe I misunderstood him but it seemed to me like he was arguing the luminol reaction alone was proof of blood, so again, correct me if I'm wrong.
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I don’t know if you mean confirmatory tests only (antibody based) or if you include other presumptive tests such as TMB in your comment. If you include other presumptive tests, then we should point out that Luminol is not just “less specific” than other tests, it is actually
more specific than TMB and “by far more sensitive” as for literature (that doesn’t mean TMB laboratory tests with a smaller sensitiveness gap don’texist, they exist but they are still less sensitive then luminol and even less specific than other TMB tests.) .
And above all, both TMB and confirmative tests are indirect tests (made on a sample, not on the stain).
I do think the luminol reaction “alone” is proof of blood, if by the word “alone” you mean
as only finding detected chemical means. If you include all findings and all methods of assessment about the luminol footprints, then luminol is obviously not the
only piece of information you have about the stain. It is the only one that is obtained through laboratory methods, the other findings are from other means of observation.
Welcome, Samzilla.
The situation in the Knox-Sollecito trial regarding luminol is basically this:
1. Six weeks after the initial forensic investigation and after they closed the crime scene and left it like
this (the photos at left are how it was when the murder was discovered, the ones at right how it looked when they laid the luminol) the police didn't have any real evidence against Amanda and Raffaele and went back to the scene looking for some. They laid luminol in the hallway, Filomena's room and Amanda's room and did TMB tests which were negative.
2. Writing up her forensic report, the RTIGF, Patrizia Stefanoni included the luminol positives but omitted the TMB negatives.
3. When in court and asked about a luminol hit and whether they did any more tests she replied something to the effect of 'we only laid luminol there.'
This is absolutely false. It has been already shown that such narrative about Stefanoni’s statements is a lie, Kaosium only refuses to accept it.
The truth is Stefanoni declared immediately, on her first hearing (Oct. 2008) that “we tried several kinds of tests” on the luminol stains but because of “trials we did in our laboratories” she said "we know that those tests" on "latent stains" “most often yield a false negative”.
It is not true that said “we only laid luminol there” when asked about a trace, but (this was one of the subsequent instances) there was one moment when lawyer Maori (IIRC) using a laser pointer on a picture asked her if on a specific point (below the door) they “laid other chemical substances”.
Besides this, let’s not forget that defence expert prof. Potenza was assisting the testing session in the corridor on Dec. 17.
4. Late in the trial the prosecution was ordered to reveal documents they had not given the defense, in there were the results of the TMB tests on the luminol hits that were negative and they'd omitted from the RTIGF and lied about in court.
Let’s not forget that the prosecution answered “yes” to the defence request and offered to give the documents themselves.
Let’s also not forget that nobody among prosecution or Stefanoni was found having lied in court about such tests. Your statement above "they lied about in court" - one of the many, delusional innocentisti myths - is manifestly unfounded and false.