54 Morales; the homes of the defendants were not searched; there was no investigation to see if the records for when the alleged murderers went on and off duty and the records for handing in and taking out their officially issued arms from the armories had been falsified; there was no investigation about the vehicle used by the abductors of the four youths whose corpses were found in the San Nicolás Woods although one witness provided the license plate number; and there was no investigation of the threats that some witnesses suffered and that obviously hampered investigations. 232. Regarding the evaluation of the evidence, the domestic courts rejected certain important testimonies as irrelevant or totally or partially disqualified them, applying criteria that should be contested. Thus, for example, the mothers of three of the victims were disqualified as witnesses owing to their relationship to the victims. The witness who stated that she had been submitted to abduction and ill-treatment similar to those suffered by the four youths in this case, was rejected because she had been a victim of the very facts that she described. Several testimonies were declared to be “irrelevant” without any explanation, although they provided revealing elements about the way in which the facts occurred and contributed to identify those responsible. The report resulting from the police investigation ordered by the judges themselves, to support the judicial proceedings, was rejected as not being “sufficient evidence”. The testimonial statements of the authors of these reports were also rejected because, neither “directly nor indirectly do they indicate the defendants to be [the perpetrators]” – it is worth clarifying that both the conclusions of these reports and the statements of the police investigators who prepared them before the domestic judicial authorities and before this Court, firmly asserted that the perpetrators of the murders had been the two police agents identified by the witnesses. The statement of another witness was ignored because he was a person who worked for the welfare of ‘street children’, which revealed an alleged direct interest in the case. The lack of precision in which certain witnesses incurred – whose statements were taken many months after the events had occurred – on the circumstances at the time when the events occurred, were used as grounds for the total rejection of these statements, although they provided revealing information on other aspects of the events under investigation that was consistent and concurring. With regard to the ballistic test, according to which the bullet found near the body of Anstraum Aman Villagrán Morales had been fired by an arm assigned to one of the accused policemen, the domestic judges reasoned that this did not prove that the arm had been used by the defendant. Confronted by two divergent official communications from the police force about whether or not this same defendant was on duty when the homicide of the youth Villagrán Morales was committed, the said judges abided by the one that was most favorable to the interests of the defense of the accused policemen, without any explanation and without inquiring into the reasons for the contradiction. 233. If we consider how those judges proceeded as a whole, it is evident that they fragmented the probative material and then endeavored to weaken the significance of each and every one of the elements that proved the responsibility of the defendants, item by item. This contravenes the principles of evaluating evidence, according to which, the evidence must be evaluated as a whole, in other words, taking into accounts mutual relationships and the way in which some evidence supports or does not support other evidence. Consequently, the State failed to comply with the obligation to carry out an effective and adequate investigation of the corresponding facts, in violation of Article 1.1 of the American Convention, in relation to its Article 8.