5 followed the vehicle and interviewed a member of the paramilitary group as well as a member of the National Guard who collaborated with said group. However, the petitioners say that, despite that information, they excluded from their lines of investigation the individualization of State agents who could have been implicated in the attack. 23. The petitioners also claim that the State violated Article 4(1) of the American Convention to the detriment of Yelitze Moreno de Castillo and Luis César Castillo Moreno, given that in the attack of August 27, 2003, their lives had been seriously endangered and the fact that they were not killed was a matter of chance.6 24. The petitioners charge that the State violated Articles 5(1) and 5(2) of the American Convention, in connection with Article 1(1) thereof, to the detriment of Yelitze Moreno de Castillo and Luis César Castillo Moreno. According to the petitioners, the responsibility of the State is based on three factors: first, the lack of an effective investigation of the acts that caused injuries to the physical and psychological integrity of Yelitze Moreno de Castillo and Luis César Castillo Moreno; second, the suffering endured by Yelitze Moreno de Castillo and the next of kin of Joe Luis Castillo González as a result of the impunity that continues to surround the facts; and, third the changes in the conditions of existence and life plans of Yelitze Moreno de Castillo and Luis César Castillo Moreno. 25. In this regard, the petitioners argue that the failure to investigate the events and the impunity in which the facts remain create a propitious climate for a repetition of acts of this nature to the detriment of Yelitze Moreno de Castillo and the child Luis César Castillo Moreno. In addition, the incident coupled with the anxiety and suffering caused by the absence of an effective response from the authorities and the failure to investigate and punish those responsible has harmed their psychological and emotional integrity. According to the petitioners, in 2004, Yelitze Moreno de Castillo had to be referred for psychiatric treatment after presenting panic symptoms and generalized anxiety, accompanied by physical disorders, as a result of the fears associated with collecting information and hypotheses as to the facts. They say that Yelitze Moreno de Castillo still evinces symptoms associated with post-traumatic stress, such as flashbacks of the violence of the incident, fear of a repetition, nightmares, difficulty sleeping and relaxing, and other symptoms that have impeded her healthy development. They allege that this situation has also affected her son and immediate relatives. 26. The petitioners say that the child Luis César Castillo Moreno, who was one and a half years old at the time of the incident, reacts with panic to the sound of detonations and with anxiety to loud vehicle noises, especially those of motorcycles, and displays regressive conduct characterized by clinging to his mother and care-givers as well as inability to sleep alone, among other behaviors. 27. According to the petitioners, the State violated Article 13 of the American Convention, in connection with Articles 4(1) and 1(1) thereof, to the detriment of Joe Luis Castillo González. The petitioners claim that the murder of Joe Luis Castillo González was prompted by his work as a human rights defender and, therefore, his killing constituted a means of deprivation of his right to freedom of thought and expression, as well as that of Venezuelan society as a whole. They also hold that the killing of Joe Luis Castillo González impaired the work of the Vicariate of Machiques in reporting human rights violations, and to that extent constituted, in turn, a form of indirect coercion of the right to freedom of expression of the human rights defenders that worked at the Vicariate. 28. The petitioners also assert that the State violated Article 16 of the American Convention, in connection with Article 1(1) thereof, to the detriment of Joe Luis Castillo González. According to the petitioners, given that the murder of Joe Luis Castillo González was motivated by his work in defense of human rights, it constituted a violation of the right to freedom of association. They also argue that his killing had an intimidatory effect on the other human rights defenders who worked at the Apostolic Vicariate of Machiques, so much so that in the wake of the events, the staff were collectively given leave and the 6 The petitioners refer to I/A Court H.R., Case of the Rochela Massacre v. Colombia, Judgment of May 11, 2007. Series C, No. 163, pars. 124 and 128. Petitioners’ brief on merits received at the IACHR on July 13, 2007.