A selection of key paragraphs can be found below the judgment.
131. The Court considers that where an individual makes a credible assertion that he has suffered treatment infringing Article 3 at the hands of the police or other similar agents of the State, that provision, read in conjunction with the State’s general duty under Article 1 of the Convention to “secure to everyone within their jurisdiction the rights and freedoms defined in … [the] Convention”, requires by implication that there should be an effective official investigation. As with an investigation under Article 2, such investigation should be capable of leading to the identification and punishment of those responsible (see, in relation to Article 2 of the Convention, the McCann and Others v. the United Kingdom judgment of 27 September 1995, Series A no. 324, p. 49, § 161; the Kaya v. Turkey judgment of 19 February 1998, Reports 1998-I, p. 324, § 86; and the Yaşa v. Turkey judgment of 2 September 1998, Reports 1998-VI, p. 2438, § 98). Otherwise, the general legal prohibition of torture and inhuman and degrading treatment and punishment would, despite its fundamental importance (see paragraph 119 above), be ineffective in practice and it would be possible in some cases for agents of the State to abuse the rights of those within their control with virtual impunity (see the Assenov and Others judgment cited above, p. 3290, § 102).