A/HRC/28/68/Add.3 must prove that the torture or ill-treatment did not occur and judges must order the immediate exclusion of the evidence and the conduct of the relevant investigations. 57. Recently, there have been positive jurisprudential and practical developments. The Supreme Court ruled that evidence obtained on the basis of unlawful detention and in violation of fundamental rights is inadmissible and ordered the release of a detainee who had been sentenced almost exclusively on the basis of evidence obtained under torture.14 In another decision, the Supreme Court established the obligation of judges to institute two independent proceedings in response to a complaint of torture, one to investigate the allegations and the other to determine the necessity of excluding evidence, thereby avoiding the postponement of a decision on admissibility to the sentencing stage and, rightly, separating the exclusion of evidence from the outcome of the investigation. 15 In March 2014, the Attorney General’s Office withdrew charges in a case in which the application of the Istanbul Protocol indicated that the persons detained for alleged involvement in the explosion of a car bomb had been victims of torture. The Special Rapporteur trusts that these developments at the federal level will be consolidated and will be extended to the state level. 7. Monitoring 58. Pursuant to the Optional Protocol to the Convention against Torture, Mexico has had a national preventive mechanism since 2007, which operates within the orbit of the National Human Rights Commission. The mechanism is empowered to visit, without prior notification, all places in the national territory where there are persons deprived of their liberty. Between 2007 and April 2014, the mechanism made 3,181 visits and issued 53 reports with recommendations aimed at various authorities. The state human rights commissions also visit and monitor conditions in detention centres, as do civil society organizations, although the latter reported severe restrictions on doing so. 59. The Special Rapporteur was informed that the national preventive mechanism does not use the opportunity afforded by its visits to draw up a record of individual complaints of torture and ill-treatment. It also does not follow up such complaints. Moreover, not all its visits result in reports and public findings and there is little coordination with civil society in doing preventive work. The Special Rapporteur is concerned at the assertion by the authorities of the Federal Investigation Centre, where arraigo detainees are held, that the mechanism can visit the Centre only with the authorization of the Public Prosecution Service. 60. Judicial oversight of the enforcement of sentences is a fundamental guarantee for preventing torture and ill-treatment. The 2008 constitutional amendments laid the bases for judicial oversight of the enforcement of sentences. However, Mexico still does not have a federal court, and a court in each state, that directly oversees the conditions in which detainees serve their sentences or the disciplinary measures imposed on them. Even though there is judicial oversight of the enforcement of precautionary measures such as arraigo, most detainees in the Federal Investigation Centre had not seen the supervisory judge. A majority of states have enacted laws on judicial oversight of enforcement of sentences, but either the laws tend to be defective and restrictive with regard to the judge’s powers to monitor conditions of detention or else the concept is inoperative. The Special Rapporteur was informed that the Federal Council of the Judiciary has begun to appoint supervisory judges and that the Federal Congress is currently discussing sentence enforcement bills that provide for judicial oversight of the enforcement of any measure of deprivation of liberty in 14 15 14 Supreme Court of Justice, Amparo Review No. 703/2012. Supreme Court of Justice, Direct Amparo Review No. 90/2014. GE.14-25288