operation of this nature 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.”157 In this case, although there is witness testimony to the effect that Mr. Valencia was told to surrender and that "nothing would happen to him," according to a number of witnesses, those statements were made amid continuous gunshots, which, according to the testimony of Luis Piedra Meza were “designed to intimidate the Policeman.” 185. The Commission observes that the shooting during the operation continued for the space of five minutes (supra, par. 177. c) and approximately six shots made direct impact on the place where Mr. Valencia was situated, including places such as windows and masonry (supra, par. 80). Although the domestic inquiry failed clearly to determine the number of shots that they fired, according to the witness testimony, there may have been between five and 10 shots (supra, par. 68) and, based on the number of cartridges missing from the rifle that one of them was carrying, Cabezas alone may have fired as many as 18 rounds. 158 By contrast, even though it was also not consistently determined how many shots Mr. Valencia fired, the Commission finds that according to an expert report on "the examination" of the firearm that he was carrying, it was established that only six rounds in the six-bullet cylinder were discharged (supra, par. 76). If the suicide theory were true, at least one of those three shots would have been made inside the security guard's quarters. No further steps were taken to determine if the other two were fired before that at the wounded policemen, which would cast into doubt the policemen's account that Mister Valencia fired out at them from his hiding place. 186. In light of the foregoing, the Commission notes that in the evidence available following the State's deficient investigation: (i) there was no consistent evidence suggesting that the policemen necessarily had to use lethal force to repel an imminent attack and protect their lives and those of the people at the sports complex; and (ii) there is nothing to suggest that they attempted other, less lethal means of intervention in the case, or considered if the level of force that they used was proportionate to the level of resistance offered. 187. The Commission considers that even assuming that Mister Valencia had fired the first shot from the security guard's quarters—something that was not clarified in the domestic investigation- according to principles of international law, moderation in the use of force must be constantly adjusted during an operation in line with changes in specific circumstances and taking into account the criteria of necessity and proportionality. Therefore, use of force was not authorized against persons who no longer posed a threat, “even if a failure to use lethal force [might have resulted] in the opportunity to arrest the fugitive being lost.”159 Based on the available evidence, the Commission finds that even though the people who were in the sports complex had been moved away and Mr. Valencia had been neutralized in a specific place, lethal force was the only means used against him, its use continued for approximately 5 minutes, and it only ended when he was dead. 188. Regarding the use of lethal force "to intimidate" Mr. Valencia Hinojosa, the Commission considers it relevant to point out that while state agents are authorized to use force in certain circumstances to protect their lives and those of others, they also have a duty to protect the life of the person whom they seek to neutralize. In this connection, the Commission reiterates that it is necessary permanently to apply throughout an operation 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. 160 157 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 ii). 158With respect to the number of shots made by the policemen Cabezas and Piedra, the Commission notes that: (i) with regard to the Glock that Second Lieutenant Piedra was carrying, the number was not investigated; however, according to a number of witnesses, he did fire; ii) regarding the rifle that Mr. Cabezas was carrying, the testimony of Luis Alfredo Verdezoto indicates that upon being returned his rifle there were 18 cartridges missing and, according to the testimony of Ana Teresa García Espinoza, the policeman with the rifle wanted to shoot but "he had run out bullets.” 159 ECHR, Case of Kakoulli v. Turkey, Application No. 385/97. November 22, 2005, § 108. 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 ii). 160