The European Court’s approach to “thoroughness” can be observed in the following judgment: “[…] The investigator did accept the police officers’ testimonies as credible, despite the fact that their statements could have constituted defence tactics and have been aimed at damaging the applicant’s credibility. In the Court’s view, the prosecution inquiry applied different standards when assessing the testimonies, as that given by the applicant was deemed to be subjective but not those given by the police officers. The credibility of the latter testimonies should also have been questioned, as the prosecution investigation was supposed to establish whether the officers were liable on the basis of disciplinary or criminal charges (see Ognyanova and Choban v. Bulgaria, no. 46317/99, § 99, 23 February 2006). ”136 This approach is clearly in line with the CEHRC Opinion, which outlines the obligations of the authorities in: “pursuing lines of inquiry on grounds of reasonable suspicion and not disregarding evidence in support of a complaint or uncritically accepting evidence, particularly police testimonies, against a complaint.”137 4.2.5 Investigations should be comprehensive in scope. Investigations must be comprehensive, particularly where they involve more than one incident or a complex set of interrelated facts. This reflects the content of the CPT’s visit reports: “The investigation must also be conducted in a comprehensive manner. The CPT has come across cases when, in spite of numerous alleged incidents and facts related to possible ill-treatment, the scope of the investigation was unduly circumscribed, significant episodes and surrounding circumstances indicative of ill-treatment being disregarded.”138 An example of such a set of facts is where ill-treatment occurs during a preplanned police operation involving the use of force. Investigators must establish that the operation was planned and carried out with a proper risk assessment and precautions against excessive use of force, and then examine whether the action was proportionate in terms of the overall aim pursued.139 Other 136. Barabanshchikov v. Russia, Judgment of 8 January 2009, application no. 36220/02, paras. 46, 59, 61. 137. CEHRC’s Opinion, para. 69. 138. 14th General Report on the CPT’s activities, CPT/Inf (2004) 28 para. 33. See also the CPT’s Report on the visit to Albania carried out from 13 to 18 July 2003, CPT/Inf (2006) 22, para. 30. 139. See Tzekov v. Bulgaria, Court’s Judgment of 23 February 2006, application no. 45500/99 and Nachova v. Bulgaria, Judgment of 26 February 2004, applications nos. nos. 43577/98 and 43579/98 with further references. Effective investigation of ill-treatment – Guidelines ► Page 52