The occurrence of human rights violations during assemblies triggers a duty on the part of the authorities to investigate. The joint report on the proper management of assemblies states in this regard:
This duty notably comes into play when deaths or injuries occur. The UN Human Rights Council has urged States to:
The legal obligation to investigate deaths, injuries and inhuman or degrading treatment occurring in connection with assemblies is confirmed by the jurisprudence of a range of international courts and mechanisms. The ECtHR has held in this regard:
The general legal prohibition of arbitrary killing and torture and inhuman or degrading treatment or punishment by agents of the State would be ineffective in practice if there existed no procedure either for reviewing the lawfulness of the use of lethal force by State authorities, or for investigating arbitrary killings and allegations of ill-treatment of persons held by them.
Thus, having regard to the general duty on the State under Article 1 of the Convention to “secure to everyone within their jurisdiction the rights and freedoms defined in [the] Convention”, the provisions of Articles 2 and 3 require by implication that there should be some form of effective official investigation, both when individuals have been killed as a result of the use of force by, inter alia, agents of the State … and where an individual makes a credible assertion that he has suffered treatment infringing Article 3 of the Convention …
The duty to investigate death or ill-treatment applies regardless of whether private actors or government agents are responsible. It is important to note that the awarding of damages cannot come in the place of the duty to investigate. This duty can generally only be satisfied through criminal law.
The ECtHR has underlined that the duty to investigate applies to any demonstration, “however illegal it may have been.”