30 weapon had been used in other crimes attributed to the “golden boys;” investigate any specific motives Otávio Ernesto Moreira may have had to murder Gilson Nogueira de Carvalho and look into his friendship and employment relationship with other members of the civil police who may have had cause to order the homicide; add to the case file on the death of Gilson Nogueira de Carvalho a copy of the investigation into the death of Antônio Lopes, and study any linkage between the two crimes; and repeat the questioning of all witnesses, taking into account new investigative possibilities suggested by the ballistics tests on December 10, 1998; ii. both the police investigation and the judicial process carried out against the only person charged with the crime evidenced clear errors that hindered clarification of the circumstances of death, and will continue to do so. Examples of these errors include: both the court that was the venue of the jury trial, and the State Court of Rio Grande do Norte refrained from commenting on the request to add to the court records a copy of the judicial file on the investigation into the death of Antônio Lopes; the president of the jury denied a request by the parents of Gilson Nogueira de Carvalho to allow the witness Angélica da Silva Campelino to take the stand, but did allow the defense team of the accused to add to the case file a technical note of doubtful provenance that challenged the findings of the report produced by the Federal Police National Bureau of Criminology; and clear contradictions between testimonies submitted in the trial were not reconciled. Since the time Otávio Ernesto Moreira was acquitted, the State has not undertaken a new investigation to determine the perpetrators of the death of Gilson Nogueira de Carvalho; iii. the parents of Gilson Nogueira de Carvalho seized all the remedies that, in theory, were available, but they were systematically denied; and iv. the lack of due diligence in the process of investigation and collection of essential evidence, without which judicial processes cannot be conducted, constituted a breach of Articles 8 and 25 of the Convention. The mechanical application of procedural formalities, condemned in advance to be fruitless, does not qualify as an effective search for justice. Arguments of the representatives 69. The representatives claim, inter alia, that: a) the Court is competent to judge violations of Article 4 of the Convention in the instant case because of the State's failure to investigate the facts surrounding the murder of Gilson Nogueira de Carvalho, event though his death preceded the State's recognition of the jurisdiction of the Court. The guarantee of the right to life includes the duty to investigate, which is conceptually distinct from the substantive duty to protect persons from being illegally deprived of life. The failure of the State to investigate effectively the death of Gilson Nogueira de Carvalho constitutes a breach of Article 4 of the American Convention, regardless of any violations the Court may declare to Articles 8 and 25 thereof; b) concerning the right to a fair trial and the right to judicial protection: i. State authorities failed to conduct a conscientious, effective investigation in this case. Despite evidence obtained in the police investigation and contradictory statements made to the police, the Office of the Public Prosecutor filed charges only against former police officer Otávio Ernesto Moreira for the death of Gilson Nogueira de Carvalho, ignoring the fact that the homicide was committed by three principals.