they were detained, the European Court of Human Rights held that changes to that national law and practice were necessary to ensure preventive remedies and that therefore had been a violation of Article 3 of the ECHR and prohibition of inhuman and degrading treatment.302 17. A system of regular visits by independent bodies to places of detention is also considered to minimise the risk of torture and ill treatment occurring. 303 Duty to criminalise torture 18. Article 4 of UNCAT requires states to adopt legislation to criminalise torture in domestic law.304 19. This applies even to those states where international law is directly applicable at the national level.305 Duty to investigate 20. This State has the duty to investigate allegations of torture or other ill treatment,306 as soon as the State is aware of the allegations,307 and even if there has not been a formal complaint.308 It is considered to be part of the requirement for the victim to know the truth. Where an individual is in good health when they are taken into custody but has injuries when they are released, the State will bear the burden of proving how the injuries occurred. 309 The Istanbul Protocol on the Effective Investigation and Documentation of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment310 sets out some general principles that should apply to such investigations. These include that investigations:  identify measures to prevent future instances;  should comply with international standards;311  are carried out promptly. Eighteen days between the allegation being reported and the investigation starting was considered too long;312  clarify the facts and be ‘capable of leading to the identification and punishment of those responsible’; 313  meet the highest professional standards; 302 European Court of Human Rights, Neshkov and others v Bulgaria, 27 January 2015 (pilot judgment). See ‘Monitoring and inspecting places of detention’ below. 304 See also Article 2(2) ICCPR. 305 CAT General Comment No.2, CAT/C/GC/2/CRP.1/Rev.4 (2007). 306 Article 12 UNCAT; Article 2, 7 ICCPR. Article 8 Inter-American Convention to Prevent and Punish Torture. 307 Inter-American Court, Servellón Garcia v Hondoras, 21 Sep 2006, para 119. 308 Articles 12, 13 and 16 UNCAT. 309 European Court, Ribitsch v Austria, 4 December 1995; Stefan Iliev v Bulgaria, 10 May 2007. 310 Office of the High Commissioner for Human Rights, Istanbul Protocol. Manual on the Effective Investigation and Documentation of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, Geneva, August 1999. 311 Inter-American Court, Vargas Areco v Paraguay, 26 September 2006. 312 CAT, Communication 59/1996, Blanco Abad v Spain, 14 May 1998. 313 European Court, Assenov and others v Bulgaria, 28 October 1998, para 102. CAT Committee Blanco Abad v Spain, ibid. 303 67