Point 1. There is no evidence to support any of your conjectures. It is Nenciniesque in its lack of factual basis. Even if true, your conjectures only point out how incompetent the FP were. They let DNA degrade and/or they failed to swab up enough to obtain profiles. You might have been on safer ground to argue that the overapplication of luminol caused degradation of the DNA, inasmuch as some literature exists to support this idea. Finally, both your explanation and overapplication fail to explain why only Ms. Knox’s DNA was found in some of the prints.
It sounds almost comical: there is no evidence, but "even if true"... The problem here is that here you are trying to work outside your area of competence. All these "conjectures" don't require any evidence. I may be wrong but, as far as I recall, it happened that some blood traces (which were visibly pure blood) picked I think from the wall several weeks later, yielded a negative DNA result. I thought this could be because of a prolonged environmental exposure within an unsafe environment.
I also recall that several blood drops yielded either a negative DNA result (such as rep. 191) or a negative TMB result (such as Knox's blood on the pillow or some of the blood drops in the downstairs apartment). I don’t think that this was caused by environmental degradation, but manifests the intrinsic uncertainty with TMB test too and its possibility to yield false negatives.
I have another objection: not only
overapplication of luminol may cause DNA degradation, its
application itself, with no mistake in it, may have a negative effect on DNA. Knox's DNA may have been more resistant if coming from more resistant and more "dry" cells such as epithelial cells instead of blood leukocytes, which are rather fragile.
Yet the fundus of your argument is that you could deduce that forensics were "incompetent". Besides the fact that this deduction would be irrelevant since the forensics are not the ones under trial (in the Erba massacre the forensic work was a complete mess, but the judge convicted anyway), I object that in fact you cannot make the deduction at all. The truth is that the Polizia Scientifica didn't have any power to decide whether and when to perform further investigations, how to manage the crime scene, what day they may come again and so on. It is the Perugian police detective authorities basically who will take those decisions. The Roman forensics are come on demand but they don't have any power about crime scene management. On Nov. 2 in the night Stefanoni wanted to go on with the forensic investigation, but she was ordered to leave, after insistent requests from paramedics.
Point 2. A true confirmatory test uses antibodies to detect substances that are unique to primate blood. It is remarkable that you still do not understand this point.
You have misunderstood. I assure I do understand what an antibody confirmatory test is. What I objected to is your adding of the adjective "true". A confirmatory test is just a confirmatory test. Doesn't have an adjective "true". I only suspected that you inserted the adjective for a rhetorical purpose, and i object to this in order to avoid confusion, since a confirmatory test does not equate to a response about "the truth".
If confirmatory tests were done but not reported, they might as well have not been done (and this would also be more evidence of withholding of data). Your position, that a confirmatory test can only confirm and not disprove the existence of blood, leads to the conclusion that once there is a positive luminol reaction, the substance must be blood and there is no further test, is wildly at odds with forensic chemistry as it is practiced today.
Not necessarily, not always, but in this case yes. The problem is that you cannot make a generalization and a standard from any situation of evidence assessment.
Evidence assessment is a kind of final, independent, let's say "sovereign" activity, can use findings from specific disciplines in a way that is not subjected to the internal requirements of other specific disciplines. You can well take some unconfirmed results and make further deductions about them, by crossing them with other information which may be not intrinsic to the finding itself or to the specific discipline. You can well derive that a substance is likely blood, for example, from the fact that it looks like a human foot and has features that are identical to peculiar stain which you know is in blood and found within the same context.
You don't "need" a confirmatory test, of any kind, in principle, for any piece of evidence. Pieces of circumstantial evidence are supposed to indicate not to confirm, their nature is to be expected to be not probative.
The final assessment of evidence is not supposed to be done by a chemist, it's done by a judge.
It is also empirically wrong (as Sarah Gino’s testimony pointed out), and some substances exist which react with luminol but not other presumptive blood tests. Draino is one, and it is likely that Comet Cleanser is another (it produces bleach when hydrated). All you have shown is that in the presence of lemon juice, TMB will not work.
You know that this is not true: there are studies from Webb et at. and Tobe et al. which find luminol far more sensitive and more specific; and you know that your lemon juice and the other study comment is false: the study cannot be reasonably reduced to the effect of lemon juice, since it can be reasonably extended to other reducing agents
As for Comet cleaner et similia: these are basically just strong oxidizing agents. They are bleaches. Their effect with luminol is known. But it is also known that bleaches at "normal use" concentration are salts that would be completely soluble in water and be thus volatile, and are known persisting as reactive to luminol only for a short time.
But also, those bleaches and strong oxidants are not plausible, because there is no reason why a person would walk bare foot after steeping their feet in bleach, and if they do so there is no reason why they would do that without producing a trail of footprint, and if such a product was used in the house so extensively to the point of dipping bare feet into it, there should be at least some evidence of such extended use and there is no evidence of that,
If every positive presumptive test were treated as certainly being from human blood, it would lead to many false convictions.
But this is a straw man, and sorry but it's completely stupid. One thing is talking about
every presumptive test be treated as certainly human blood, which is not what we are argueing about; what we are talking about is something else that is the theory that you propose: a rule saying that the fact that there isn't a chemical confirmatory test should be lead to a deduction that it is not blood.
It's a completely different story: you are trying a heap between two absolutes: from everything to zero. From objecting that "not every luminol print" without antibody test should be treated like human blood, you heap to the asserting that "no luminol print" without antibody confirmatory test should be assessed to be blood.
This is absurd.
Point 3. There are ranges of lower limits of detection reported for both compounds. Webb, Creamer, and Quickenden (2006) reported that luminol has a lower limit of detection of 1 part in 5,000,000 and hemastix (one variant of TMB) has a lower limit of detection of 1 part in 1,000,000. Therefore, your claim is that all the locations fell into a tiny window between the lower limits of detection of TMB and luminol. How likely is that, really?
But these of Quickenden & Creamer are merely the theoretical limits. In the practical use, Tobe et al. and Webb et al. have found that TMB test is unlikely to detect blood at 1:100'000 dilution, but in fact its sensitivity limit should to be assessed at a lower magnitude: 1:10’000 dilution in laboratory still yields reliable results, but not further. However, the point is that these tests are a measurement of a final dilution of the sample. They are not measurements about the stain. The problem between the two tests is that one is direct and the other is indirect. A sample may not yield remotely the same dilution of the original stain. In a sample, the collected amount should be considered an absolute amount, the dilution may become much greater as water solvent is added again on the swab.
Point 4. Your answer fails to address the question. Let me quote again what one judge said. “Thus, although I would admit the evidence in relation to the blood stains which are confirmed to be blood by scientific analysis and which produce relevant DNA profiles, I would not admit the evidence in relation to the luminol positive areas where there is no confirmatory testing.”
Of course I won't answer the question: there is no case to answer. The Supreme Court of Italy would not allow the reasoning of this judge to be part of the system. It's simply impossible for a position like that to part of the Italian justice system. In the Italian system there is no jury and the word "judge" means something else.
Point 5. Your answer is another non-answer. It disguises the fact that your position is basically that once a luminol-positive area is encountered, it is certainly blood and game over. In effect you are saying that the judges who think otherwise are fools. That is an arrogant, possibly Chauvinistic attitude.
I already answered to this, under n.2, pointing out your straw man. It's actually not me who is arrogant and tries to instruct the judges about what they should decide, telling them what is just and reasonable to do in their job of evidence assessment.
I think it's you the one stating that judges must follow a rule of
never accepting that a luminol stain is blood unless they have a confirmatory test.
You are basically dictating the rules to judges saying they should be bound within the limits of certainity of chemical science, obey to veiwpoints of chemists and not try to find out things other ways.
I am not saying that luminol reaction must always be "game over"; but on the other hand, what I am saying is that
sometimes it might be. Sometimes a finding provides a piece of information that can be used without being itself complete. Like on a situation like this, where you have to cross the chemical result with a mass of information and peculiarities that you cannot explain away easily through alternative dynamic and substance.
