Given that the prohibition of torture is of an absolute nature, enjoying a high degree of protection, the European Court of Human Rights considers it a key right. An extensive part of the paper includes an analysis of the violation of Article 3 of the European Convention for the Protection of Human Rights and Fundamental Freedoms in the context of arrests and detention in criminal proceedings. Emphasis is placed on the case law of the European Court of Human Rights in cases against Croatia in which the Court found violations of this right. In a number of cases against the Republic of Croatia, the ECtHR found a violation of Art. 3. of which a significant part relates to violations of this right by police officers and violations within the prison system. Most of the verdicts relate to violations of the procedural obligation to conduct an effective investigation. Therefore, the material and procedural aspects of the violation of Article 3, the obligation to conduct an effective investigation are analyzed and the standards of the European Court of Human Rights regarding effective investigation in the context of abuse are stated. The cases against the Republic of Croatia are analyzed separately in which a violation of Art. 3. in the context of arrest and detention.