-9663. Bearing in mind the difficulties in policing modern societies, the unpredictability of human conduct and the operational choices which must be made in terms of priorities and resources, the positive obligation must be interpreted in a way which does not impose an impossible or disproportionate burden on the authorities. Accordingly, not every claimed danger to life can entail for the authorities a Convention requirement to take operational measures to prevent that danger from materialising. For a positive obligation to arise, it must be established that the authorities knew or ought to have known at the time of the existence of a real and immediate danger to the life of an identified individual or individuals from the criminal acts of a third party and that they failed to take measures within the scope of their powers which, judged reasonably, might have been expected to avoid that danger (see the Osman judgment [...], pp. 3159-60, para. 116).203 125. In this case, the Court recognizes that the State adopted several legislative measures to prohibit, prevent and punish the activities of the self-defense or paramilitary groups (supra paras. 95(8) to 95(20)) and, in relation to the special situation in Urabá Antioqueño, the region where the jurisdiction of Pueblo Bello is located, awareness of the dangerous situation and of the need to control the zone was translated into the adoption of a series of measures to this end, such as: the creation in 1988 of the XIth Brigade in Montería and the No. 1 Mobile Brigade, and the issue of Decree No. 0678 of April 14, 1988, for the “re-establishment of public order” in this zone and creating the Military Headquarters of Urabá Antioqueño (supra paras. 95(6), 95(7) and 95(26)). Thus, it is evident that the State authorities knew about the possibility of specific danger owing to the activities of paramilitary groups or individuals that could materialize in situations that would affect the civilian population. 126. Nevertheless, these measures did not translate into the specific and effective deactivation of the danger that the State itself had contributed to creating. Owing to the interpretation given to the legal framework for many years, the State encouraged the creation of self-defense groups with specific objectives; however the latter exceeded these objectives and began to act illegally. Thus, by having encouraged the creation of these groups, the State objectively created a dangerous situation for its inhabitants and failed to adopt all the necessary or sufficient measures to avoid these groups continuing to commit acts such as those of the instant case. The declaration of the illegality of these groups should have translated into the adoption of sufficient and effective measures to avoid the consequences of the danger that had been created. While it subsists, this dangerous situation accentuates the State’s special obligations of prevention and protection in the zones where the paramilitary groups were present, as well as the obligation to investigate diligently, the acts or omissions of State agents and individuals who attack the civilian population. 127. The lack of effectiveness in dismantling the paramilitary structures can be seen also from the rationale and characteristics of the laws adopted from 1989 to date (supra paras. 95(8) to 95(20)), as well as from an examination of the quantitative and qualitative intensity of the human rights violations committed by the paramilitary groups at the time of the facts and over the following years, acting on their own or in connivance or collaboration with State agents, vis-à-vis the high rates of impunity of this type of facts. 203 Cf. European Court of Human Rights, Kiliç v. Turkey, judgment of 28 March 2000, Application No. 22492/93, paras. 62 and 63; Osman v. United Kingdom judgment of 28 October 1998, Reports of Judgments and Decisions 1998-VIII, paras. 115 and 116.