P.M. v. BULGARIA JUDGMENT 9 of leading to the establishment of the facts of the case and to the identification and punishment of those responsible. This is not an obligation of result, but one of means. The authorities must have taken the reasonable steps available to them to secure the evidence concerning the incident, such as witness testimony and forensic evidence, and a requirement of promptness and reasonable expedition is implicit in this context (see Denis Vasilyev v. Russia, no. 32704/04, § 100, 17 December 2009, with further references). The promptness of the authorities’ reaction to the complaints is an important factor (see Labita v. Italy [GC], no. 26772/95, §§ 133 et seq., ECHR 2000-IV). Consideration has been given in the Court’s judgments to matters such as the opening of investigations, delays in identifying witnesses or taking statements (see Mătăsaru and Saviţchi v. Moldova, no. 38281/08, §§ 88 and 93, 2 November 2010), the length of time taken for the initial investigation (see Indelicato v. Italy, no. 31143/96, § 37, 18 October 2001), and unjustified protraction of the criminal proceedings resulting in the expiry of the statute of limitations (see Angelova and Iliev v. Bulgaria, no. 55523/00, §§ 101-103, 26 July 2007). 65. Applying these principles to the present case, the Court notes that on 7 September 1992, the date of entry into force of the Convention in respect of Bulgaria, the investigation was dormant, no significant investigative measures having been carried out on the ground that the address of one of the suspects, Mr D.I., was unknown. It is highly significant, however, that when Mr D.I. was eventually “found” eight years later, it turned out that he had never changed his address (see paragraph 16 above). Apparently no attempts were made to establish his whereabouts during this considerable period. No consideration was given to the possibility of separating the cases against Mr T.Z. and Mr D.I. and proceeding with the case in respect of the former. In the Court’s view, the authorities’ inaction verges on arbitrariness, having regard, in particular, to the gravity of the facts and the applicant’s age at the relevant time. As a result, a number of urgent investigative measures, such as the commissioning of an expert examination of the applicant’s clothes and interviewing witnesses, were taken only many years after the rape (see paragraphs 21 and 30 above). It is to be noted furthermore that two decisions to discontinue the criminal proceedings were issued, only to be subsequently set aside by the supervising prosecutors (see paragraphs 24-34 above). 66. In view of the exceptionally slow pace of the proceedings, it is not surprising that the prosecution eventually became time-barred. The domestic courts discontinued the proceedings against one of the defendants, Mr T.Z., and although they convicted the other one, Mr D.I., they did not punish him because of the statute of limitations (see paragraphs 48-50 above). Thus, although the facts of the case and the identity of the offenders were established, albeit many years after the rape, the investigation can