CAT/C/75 page 62 295. As to paragraph 219 (c) and (g), the authorities’ obligation to respect the human rights of persons subject to criminal proceedings in accordance with article 20, paragraph II, of the Constitution, which provides that no one may be compelled to testify against himself, is emphasized in secondary legislation; article 134, penultimate paragraph, of the Federal Code of Criminal Procedure provides that: “… if an individual is detained for longer than the periods specified in article 16 of the Political Constitution, it will be assumed that he was being held incommunicado and any statements he may have made shall be invalid.” Article 8 of the Federal Act to Prevent and Punish Torture, published in the Diario Oficial de la Federación on 27 December 1991, states that no confession or information obtained by means of torture may be cited in evidence. Article 9 of the Act adds that “No confession or information made to a police authority or to the Public Prosecutor’s Office or a court authority in the absence of the accused’s defence counsel or other trusted individual and, if necessary, an interpreter shall have evidentiary value.” 296. It is thus obvious that any kind of detention incommunicado, intimidation or torture is punishable. Confessions before the public prosecutor or the judge must be made voluntarily by the accused and his defence counsel must be present at the time; otherwise, they are not valid as evidence. The rulings of the Federal judiciary have recognized and reiterated the idea that illegally obtained confessions are invalid as evidence, that the police can in no circumstances take statements as confessions and that, even if confessions are confirmed before the public prosecutor, this does not make them valid, though they may be regarded as circumstantial evidence.59 297. Since what are involved are acts prejudicial to the accused, his confession must be fully in compliance with the duty imposed by article 127 bis, paragraph 1, in relation to article 287, section II, of the Code, namely that the right of the accused to appoint counsel or a trusted individual to help him with his statement to the Public Prosecutor’s Office must be respected because, otherwise, the statement is invalid as evidence. If, therefore, that statement affords the primary grounds for a decision, the decision will breach the individual guarantees provided for in article 16 of the Constitution. 298. It is thus clear that, even when a person is brought before the Public Prosecutor’s Office to make a statement, the Office has the unavoidable obligation to respect his individual guarantees. 299. Paragraph 219 (f) of the report states that impunity appears to be the rule for police officers who engage in torture. It must be borne in mind that, under article 21 of the Constitution, the courts have sole and exclusive authority to impose penalties; this decision-making function cannot be left to the discretion of the parties, since the authority cannot be delegated to them. The Public Prosecutor’s Office is likewise responsible for prosecuting crimes, putting forward its position in the form of arguments, not decisions, since otherwise authority would be left to the discretion of one of the parties, and that would be inconsistent with Mexican constitutional principles. 300. In addition to article 21 of the Constitution, which determines who is entitled to institute criminal proceedings, several provisions in secondary legislation help determine that it is not the