E/CN.4/2003/8/Add.3 page 9 training in the federal judiciary, except in the case of the Supreme Court, which presides over the system and whose members are appointed by the Senate at the suggestion of the executive every 15 years. B. Constitutional rights and guarantees 15. The Mexican Constitution recognizes a number of rights and guarantees for individuals. One of these is the right to personal freedom. Article 16 of the Constitution stipulates, among other things, that an arrest warrant can be issued only by a judicial authority and only when there has been a complaint or accusation in respect of an act defined by the law as an offence punishable with at least a custodial sentence and when there is evidence of the corpus delicti and of the likely responsibility of the suspect. The authority issuing the arrest warrant is held strictly accountable for bringing the accused promptly before a judge. Any failure to do so is a criminal offence. The Constitution also stipulates that, in cases of flagrante delicto, any person may detain a suspect, who must be handed over without delay to the nearest authority, which must equally promptly hand the suspect over to the Public Prosecutor’s Office. 16. The Mexican system of constitutionality controls was modified in 1995 by the inclusion in the Constitution of applications for constitutional review of general legislation and regulations and constitutional disputes (art. 105); such applications, together with amparo proceedings and electoral controls, provide the means for nullifying or invalidating laws or, in general, actions by the authorities that violate the federal Constitution. 17. Amparo proceedings are the institutional mechanism that protects individual guarantees (articles 103 and 107 of the Constitution). They are intended to protect citizens from actions by State bodies that jeopardize their individual guarantees or to remedy violations of them. 18. The essential features of amparo are as follows: proceedings are initiated only at the request of one of the parties, who may be an individual or a group; it is definitive, and thus is available only once all available legal remedies have been exhausted; it can be dealt with only by the federal judiciary, it does not apply erga omnes and proceedings are stayed or set aside if a person’s legal situation changes, which prevents it from effectively protecting personal freedom (article 73 of the Amparo Act). III. CHARACTERISTICS OF CRIMINAL PROCEDURE 19. Criminal procedure generally consists of the following stages: (a) Preliminary investigation. In most cases, it is the Public Prosecutor’s Office that decides to conduct a preliminary investigation, either ex officio, particularly in the most serious cases (homicide, drug-trafficking, etc.), or following the submission of a complaint, particularly one submitted by the victim. In certain cases (defamation, slander, damage to another person’s property, etc.), it can take action only if the party affected submits a complaint. During the preliminary investigation itself, the Public Prosecutor’s Office, with the assistance of the judicial police, conducts investigations to determine the facts, find evidence of the crime and identify the alleged culprits. If a person needs to be detained for the purposes of the investigation, the Public Prosecutor’s Office has a period of 48 hours (renewable once in cases of organized crime) to