52. In that connection, for an explanation for the use of lethal force to be considered satisfactory, it must be the result of an investigation that is compatible with the guarantees of independence, impartiality, and due diligence; moreover, it must address all the elements that, according to inter-American case law, have to be present for such use of force to be justified: i. Legitimate purpose: the use of force must be addressed at achieving a legitimate purpose. ii. Absolute necessity: [I]t is necessary to verify whether other less harmful means exist to safeguard the life and integrity of the person or situation that it is sought to protect, according to the circumstances of the case. iii. Proportionality: the level of force used must be in accordance with the level of resistance offered, which implies establishing a balance between the situation that the agent is facing and his response, considering the potential harm that could be caused.45 53. Likewise, the Commission finds that the Basic Principles on the Use of Force and Firearms by Law Enforcement Officials allow law enforcement officials to use firearms “to arrest a person presenting such a danger and resisting their authority.”46 That notwithstanding, as part of the requirements for use of force to be permissible, the Principles say that: (i) it may be made only when less extreme means are insufficient to achieve these objectives; (ii) it “may only be made when strictly unavoidable in order to protect life”; (iii) law enforcement officials must give a “clear warning of their intent to use firearms”; and (iv) said warning must be given with sufficient time, unless to do so would endanger the law enforcement officials or other persons. 54. Based on the foregoing, the State must demonstrate the legitimate purpose, absolute necessity, and proportionality of the use of lethal force in the specific circumstances of each case. In addition, as a result of those principles, the Commission recalls that state agents who take part in operations must apply the criteria of “differentiated and progressive use of force, determining the degree of cooperation, resistance or violence of the subject against whom the intervention is intended and, on this basis, employ negotiating tactics, control or use of force, as required.”47 55. In the instant case, there is no dispute over the fact that, as a result of use of lethal force by agents of the Ecuadorian Navy, Luis Eduardo was wounded and later died and Andrés Alejandro was wounded. The dispute is over whether the death and injuries were the result of an armed confrontation between State agents and the fisherman, including the Casierra brothers, as the State argues, or if they were actually caused by a misuse of lethal force, given that the fisherman did not have any firearms, as the petitioners contend. 56. According to the standards described above, the Commission must analyze if the State has satisfactorily explained that the killing and wounding of the Casierra brothers was the result of a legitimate use of lethal force to repel an attack. 57. The Commission finds that the explanation offered by the State is essentially based on the conclusions reached by the authorities in the framework of the military criminal jurisdiction, where it was decided to dismiss the matter in favor of the state agents involved. 58. The IACHR notes that that investigation, as the next section of the report indicates, fell short of the standards of independence and impartiality required by the American Convention for the investigation and punishment of acts of the kind that occurred in this case. In relation to the accounts provided by those officials, the Commission considers it relevant to point out that when it comes to clarifying whether or not lethal force was legitimately used, the testimonies of the agents involved cannot automatically be presumed true; rather, they must be weighed against all the evidence contained in the record, which the State has an obligation I/A Court H.R., Case of Landaeta Mejías Brothers et al v. Venezuela, Preliminary Objections, Merits, Reparations, and Costs, Judgment of August 27, 2014. Series C. No. 281, par. 134. 46 Principles 9 and 10 of the United Nations’ Basic Principles on the Use of Force and Firearms by Law Enforcement Officials, Adopted by the Eighth United Nations Congress on the Prevention of Crime and the Treatment of Offenders, Havana, Cuba, 27 August to 7 September 1990. 47 I/A Court H.R., Case of Nadege Dorzema et al. v. Dominican Republic, Merits, Reparations and Costs. Judgment of October 24, 2012. Series C No. 251, par. 85. 45 8