32 TSALIKIDIS AND OTHERS v. GREECE JUDGMENT Convention requires that an investigation which satisfies the minimum threshold of effectiveness be conducted in order to shed light on the circumstances of the death. The fact that the investigation ultimately accepts the hypothesis of an accident has no bearing on this issue, since the obligation to investigate is specifically intended to refute or confirm one or other hypothesis (see Mustafa Tunç and Fecire Tunç v. Turkey [GC], cited above, § 133). 111. In the present case, the circumstances of Costas Tsalikidis death were not established from the outset in a sufficiently clear manner. Various explanations were possible, and none of them was manifestly implausible in the initial stages (see paragraphs 9-12 above). Thus, the State was under an obligation to conduct an investigation and the applicants were not required to have recourse to an action for damages in the circumstances of the present case. 112. In the light of the foregoing, the Court finds that the applicants exhausted the domestic remedies and were not obliged to pursue the civil remedies suggested by the Government in order to exhaust them. The Court thus considers that the Government’s objection of non-exhaustion of available domestic remedies should be dismissed and that the applicants were not provided with effective legal procedures compatible with the procedural requirements of Article 2 of the Convention. 113. Therefore, there has been a violation of Article 2 of the Convention under its procedural limb. II. ALLEGED VIOLATION OF ARTICLE 13 IN CONJUNCTION WITH ARTICLE 2 OF THE CONVENTION 114. The applicants complained that they did not have an effective remedy in connection with their complaint about the lack of effective investigation into the murder of their relative. They relied on Article 13, which reads: “Everyone whose rights and freedoms as set forth in [the] Convention are violated shall have an effective remedy before a national authority notwithstanding that the violation has been committed by persons acting in an official capacity.” A. Admissibility 115. The Court notes that this complaint is linked to the one examined above and must therefore likewise be declared admissible as far as the supplementary investigation is concerned.