73 principle of competent tribunal, and consequently, of the right to due process and a fair trial; k) some of the investigations initiated by the State after Mr. Alberto Fujimori left power have been conducted very slowly, considering that six years have elapsed since the fall of that government and more than five years since the State pledged to take measures to restitute violated rights and/or make reparations for the damage caused in the La Cantuta case. The right to a fair trial is not exhausted by the conduct of internal proceedings, it must also ensure a decision within a reasonable term, to last until an unappealable judgment is rendered, including the whole proceedings and the potential trial remedies that could be filed. In cases such as the instant case, authorities must act ex officio and launch the investigation, without leaving this burden to the initiative of the next of kin; l) besides, these investigations have not included all those allegedly responsible for the events generating the international responsibility of the State. The State has resorted to the figure of res judicata to avoid punishing some of the alleged intellectual perpetrators. This constitutes an infringement of the American Convention, inasmuch as States cannot apply domestic laws or provisions to escape the duty to investigate and punish those responsible for violations of the Convention. The reopening of investigations within domestic jurisdiction would not affect in any way whatsoever the non bis in idem principle embodied in Article 8(4) of the American Convention, since the res judicata principle never applied, because the alleged perpetrators were tried by a court which, under Article 8 of the Convention, was not competent, independent and impartial and did not satisfy the requirements of competent tribunal. This is so because the requirement of a previous acquittal is not met when said judgment lacks legal effects for standing in open contradiction to international duties. Accordingly, the Peruvian State must conduct a new trial with all the guarantees of due process in order to rectify the structural deficiencies of previous military proceedings, and m) the infringement of Articles 1, 8(1) and 25 of the Convention was effected when the State failed to conduct new investigations and domestic proceedings with enough diligence as to offset the concealment that prevailed for almost a decade, during Alberto Fujimori's administration. In this sense, the Commission insists again on the fact that the State is obliged to carry out a criminal investigation and apply criminal penalties to those responsible for the violations, also as a way to uphold the right of the victims' next of kin to know the truth. Arguments of the representatives 131. In their brief of requests, arguments and evidence, the representatives concurred with the arguments of the Commission regarding Articles 8 and 25 of the Convention in relation to Article 1(1) thereof. They added the following arguments: a) the instant case clarifies one of the distinctive features of Fujimori's regime: the control and manipulation of the legislative and judicial powers to hide the truth about egregious human rights violations and secure the impunity of those responsible;