8.1. An element of evidence of unchallengeable relevance - for the reasons explained hereinafter - is represented by the total absence of biological traces attributable with certainty to the two defendants in the murder room or on the body of the victim, whereas, instead, abundant traces surely attributable to Guede have been found.
This was an insurmountable monolithic barrier on the path taken by the fact-finding judge to arrive at the conviction of the present defendants, already acquitted previously for the murder by the Court of Appeals of Perugia.
To overcome the relevance of such a negative element - undeniably favourable to the defendants - it has been claimed in vain that, after staging the break-in, the authors of the crime performed a “selective” cleaning of the crime scene, in order to remove only those damning traces attributable to them, while leaving behind, instead, those attributable to others.
This hypothesis is patently illogical. To fully understand its degree of inconsistency it is not really necessary to appoint court experts, even if this has been requested by the defences. That such a selective cleaning, moreover capable of escaping detection by luminol, whose use by the investigators (also to find traces of non-haematic origin) is nowadays part of everyday knowledge, is, for sure, impossible, according to the basic laws of ordinary experience.
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With reference to the alleged bloody traces in the other rooms, mainly in the corridor, there is even an obvious misrepresentation of evidence. Indeed the S.A.L. of the Scientific Police (acronym of “Stato Avanzamento Lavori” [State of Work Progress], stating the progression of the scientific investigations and their results) had excluded, thanks to the use of a specific chemical reagent [TMB], that the traces highlighted by luminol in the concerned rooms were of haematic nature. These papers, even if duly filed into the trial documents, have been completely neglected.
Not only that, but it is also patently illogical, in this context, the reasoning of the fact finding judge, who (on page 186) reckons being able to overcome the defensive objection that the luminescent bluish reaction generated by luminol can be produced also by substances different from blood (for instance, leftovers of cleaning detergents, fruit juices and many others), by arguing that the reasoning, while theoretically correct, has however to be “contextualised”, meaning that if the fluorescence occurs at a place where a murder occurred, the reaction cannot be but connected with haematic traces.
The weakness of the argument is such, already at first sight, that it does not require any confutation, since to reason in that way one should also surmise that the house on via della Pergola was never the object of cleanings nor was a “lived” location [i.e. with people living and doing things in it].
This observation hence allows to categorically exclude that those traces were made of blood and willfully removed in that circumstance.
