ERGI JUDGMENT OF 28 JULY 1998 26 81. The Court, having regard to the Commission’s findings (see paragraphs 34–41 above) and to its own assessment, considers that it was probable that the bullet which killed Havva Ergi had been fired from the south or south-east, that the security forces had been present in the south and that there had been a real risk to the lives of the civilian population through being exposed to cross-fire between the security forces and the PKK. In the light of the failure of the authorities of the respondent State to adduce direct evidence on the planning and conduct of the ambush operation, the Court, in agreement with the Commission, finds that it can reasonably be inferred that insufficient precautions had been taken to protect the lives of the civilian population. (ii) As to the alleged inadequacy of the investigation 82. In addition, the Court has attached particular weight to the procedural requirement implicit in Article 2 of the Convention. It recalls that, according to its case-law, the obligation to protect the right to life under Article 2, read in conjunction with the State’s general duty under Article 1 to “secure to everyone within [its] jurisdiction the rights and freedoms defined in [the] Convention”, requires by implication that there should be some form of effective official investigation when individuals have been killed as a result of the use of force by, inter alios, agents of the State (see the above-mentioned McCann and Others judgment, p. 49, § 161; and also the Kaya v. Turkey judgment of 19 February 1998, Reports 1998-I, pp. 322, 324, §§ 78, 86). Thus, contrary to what is asserted by the Government (see paragraph 75 above), this obligation is not confined to cases where it has been established that the killing was caused by an agent of the State. Nor is it decisive whether members of the deceased’s family or others have lodged a formal complaint about the killing with the relevant investigatory authority. In the case under consideration, the mere knowledge of the killing on the part of the authorities gave rise ipso facto to an obligation under Article 2 of the Convention to carry out an effective investigation into the circumstances surrounding the death. 83. However, the Court is struck by the heavy reliance placed by Mustafa Yüce, the public prosecutor who had the obligation to carry out an investigation into Havva Ergi’s death, on the conclusion of the gendarmerie incident report that it was the PKK which had shot the applicant’s sister (see paragraph 43 above). The prosecutor had explained to the delegates that only if there had been any elements contradicting this conclusion would he have considered that any other investigatory measures would have been necessary (see paragraph 28 above). He also seemed to consider that the onus was on the deceased’s relatives to alert him to any suspicion of wrongdoing on the part of the security forces and they had not approached him in this case (ibid.). In the absence of any such elements of suspicion, he had issued a decision of lack of jurisdiction indicating that the PKK was