Key paragraph(s) can be found below the document.
324. In order to be “effective” as this expression is to be understood in the context of Article 2 of the Convention, an investigation into a death that engages the responsibility of a Contracting Party under that Article must firstly be adequate. That is, it must be capable of leading 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. Any deficiency in the investigation which undermines its ability to identify the perpetrator or perpetrators will risk falling foul of this standard (see Tahsin Acar v. Turkey [GC], no. 26307/95, § 223, ECHR 2004‑III).
325. Secondly, for the investigation to be “effective” in this sense it may generally be regarded as necessary for the persons responsible for it and carrying it out to be independent from those implicated in the events. This means not only a lack of hierarchical or institutional connection but also a practical independence (see Tahsin Acar, cited above, § 222). What is at stake here is nothing less than public confidence in the State’s monopoly on the use of force.