147. In addition, the American Convention expressly recognizes the right to personal integrity, a juridical right the protection of which is the main purpose of the peremptory prohibition of torture and cruel, inhuman or degrading treatment or punishment.176 In its case law, this Court has consistently considered that this prohibition has become ius cogens.177 In this way, an international legal system has been created for the absolute prohibition of all forms of torture, both physical and mental and, regarding the latter, it has been recognized that the threats and the real danger of subjecting a person to severe physical harm produces, in certain circumstances, such moral anguish that it may be considered “mental torture.”178 Added to this, the Court has already established that “[t]he violation of an individual’s right to physical and mental integrity is a type of violation that has various levels, ranging from torture to other types of abuse or cruel, inhuman or degrading treatment, the physical and mental consequences of which vary in intensity depending on endogenous and exogenous factors that must be demonstrated in each specific situation.”179 148. The rights to life and to personal integrity are essential in the Convention. Under Article 27(2) of this treaty, these rights form part of the non-derogable nucleus, because they cannot be suspended in case of war, public danger or other threats to the independence or security of the States Parties.180 In addition, article 4 of Protocol II Additional to the Geneva Convention indicates that “violence to the life, health and physical or mental well-being of persons [who do not take a direct part or who have ceased to take part in hostilities], in particular murder as well as cruel treatment such as torture, mutilation, or any form of corporal punishment, [… is] and shall remain prohibited at any time and in any place whatsoever.” It also emphasizes that it is prohibited to order that there shall be no survivors. Article 13 also specifies the obligation to protect the civilian population and individual civilians unless and for such time as they take a direct part in hostilities, when stating that “they shall enjoy general protection against the dangers arising from military operations” and that “they shall not be the object of attack.” 149. As regards Article 7 of the Convention, this Court has stated that it establishes guarantees that represent limits to the exercise of authority by State agents. These limits apply to the State’s instruments of control, one of which is detention. The said measure must be in keeping with the guarantees recognized in the Convention, provided that its application is exceptional in nature and respects the principle of the presumption of innocence, and the principles of legality, necessity and proportionality essential in a democratic society.181 This Court’s consistent case law recognizes that when individuals are subjected to deprivation of liberty in the custody of official control agencies, State agents or private individuals acting with their acquiescence or tolerance that practice torture and murder with impunity, represent, in itself, this represents a violation of the obligation of prevention of violations of the right to personal integrity.182 176 Cf. Case of Ximenes Lopes v. Brazil. Merits, reparations and costs. Judgment of July 4, 2006. Series C No. 149, para. 126, and Case of the Barrios Family v. Venezuela, para. 50. 177 Cf. Case of Cantoral Benavides v. Peru. Merits. Judgment of August 18, 2000. Series C No. 69, para. 95, and Case of the Barrios Family v. Venezuela, para. 50. 178 51. 179 Cf. Case of Cantoral Benavides v. Peru. Merits, para. 102, and Case of the Barrios Family v. Venezuela, para. Case of Loayza Tamayo v. Peru. Merits, para. 57, and Case of the Barrios Family v. Venezuela, para. 52. 180 Cf. Case of Baldeón García v. Peru. Merits, reparations and costs. Judgment of 6 April 6, 2006. Series C No. 147, para. 82, and Case of González et al. (“Cotton Field”) v. Mexico. Preliminary objection, merits, reparations and costs. Judgment of November 16, 2009. Series C No. 205, para. 244. 181 Cf. Case of the "Children’s Rehabilitation Institute" v. Paraguay. Preliminary objections, merits, reparations and costs. Judgment of September 2, 2004. Series C No. 112, para. 228, and Case of the Barrios Family v. Venezuela, para. 53. 182 Cf. Case of Velásquez Rodríguez v. Honduras. Merits, para. 175, and Case of the Río Negro Massacres v. Guatemala, para. 117. 46