The Court has endorsed the CPT standards in this area, as well as some of the stipulations of the Istanbul Protocol, as important elements in fulfilling the obligation to effectively investigate, particularly from the perspective of gathering evidence.49 Moreover, medical professionals owe obligations both to the persons they treat or examine and to society at large, which has an interest in ensuring that justice is done and that perpetrators of abuse are brought to justice.50 2.2.5 The right of access to a doctor of the detainee’s choice demands direct and unimpeded access to the services of recognised forensic doctors. Forensic medical evidence is often crucial to the effective investigation of alleged ill-treatment. Its importance is repeatedly emphasised by the Court: “The authorities must take whatever reasonable steps they can to secure the evidence concerning the incident, including inter alia forensic evidence. Any deficiency in the investigation which undermines its ability to establish the cause of injury or the person responsible will risk falling foul of this standard (see Batı and Others v. Turkey, nos. 33097/96 and 57834/00, § 134, ECHR 2004‑IV (extracts)). The Court therefore considers that the failure to secure the forensic evidence in a timely manner was one of the important factors contributing to the ineffectiveness of the investigation in the present case. A timely medical examination could have enabled the medical expert to reach a more definitive conclusion as to the time of infliction and cause of the injuries.”51 Similarly, the CPT emphasises that there should be no “barriers” between forensic doctors and persons alleging ill-treatment, whether or not the services of such doctors have been formally requested by investigative, prosecutorial or other officials.52 It has further specified that persons who allege ill-treatment by members of law enforcement or security agencies should be able to be examined by a recognised forensic doctor at their own initiative, without prior authorisation from an investigating or judicial authority, and regardless of whether they are deprived of their liberty.53 49. Mehmet Eren v. Turkey, Judgment of 6 April 2004, application no. 21689/93, para. 355. 50. See also the comments on Guideline 2.3.4, below. 51. Mammadov (Jalaloglu) v. Azerbaijan, Judgment of 11 January 2007, application no. 34445/04, para. 74. 52. See, for example, the CPT’s Report on the visit to Albania carried out from 23 May to 3 June 2005, CPT/Inf (2006) 24, para. 49. 53. See CPT’s Report on the visit to Russia carried out from 27 April to 6 May 2011, CPT/Inf (2013) 1, para. 28. Explanatory note ► Page 29