well-founded reasons for the measure, what is clear is that the preventive detention was ordered [...] without proving necessity, and it was implemented within the framework of legislation that was contrary to the American Convention. Consequently, the State’s argument is not sufficient to consider the preventive deprivation of liberty to be in accordance with the Convention. 53 81. The Court concludes, therefore, that the order for the preventive detention of Mr. Carranza was arbitrary, in violation of Articles 7(1) and 7(3) of the American Convention on Human Rights, in conjunction with its Articles 1(1) and 2, given that it was issued without motivation proving necessity and it was based on a law that, in establishing the appropriateness of preventive detention automatically, as described above (supra para. 78), was contrary to the Convention. B.2 Review of preventive detention 82. What must be examined now is whether maintaining or prolonging the preventive detention was appropriate in this case. 83. The Court has determined that national authorities are the ones responsible for assessing the appropriateness of their precautionary measures pursuant to their own laws. Preventive detention should be subject to periodic review so that it is not prolonged when the reasons for its use no longer exist. The judge should periodically assess whether the causes, necessity, and proportionality of the measure have changed, and whether the length of the detention has exceeded the limits of the law and of reason. If at any point it appears that the preventive detention does not meet those conditions, release must be ordered. In reviewing the continuation of the measure, the authorities must give sufficient evidence of the reasons for maintaining the restriction of liberty, which, in order to be compatible with Article 7(3) of the American Convention, must be based on the need to ensure that the defendant does not impede the efficient conduct of the investigations or evade justice. In the same way, every time the prisoner’s release is requested, the judge must demonstrate at least minimally the reasons for maintaining the preventive detention. 54 84. This Court notes that in this case the preventive detention lasted as long as the criminal trial, and it ended with the court conviction. There is no evidence that during that period the legal authorities carried out any review of the continued appropriateness of the preventive detention. This is despite the fact that Mr. Carranza requested his release in September 1995 (supra para. 44); the legal authorities did not respond in any way. 85. In view of the above, this Court concludes that the preventive detention of Mr. Carranza was implemented arbitrarily because it was not reviewed periodically, violating Articles 7(1) and 7(3), in conjunction with Article 1(1), of the Convention. B.3 Reasonableness of the length of the preventive deprivation of liberty 86. The Court has noted that Article 7(5) of the Convention imposes limits on the length of preventive detention and, consequently, on the authority of the State to attain the goals of the trial through this precautionary measure. When the length of a preventive detention is unreasonable, the State will be able to restrict the liberty of the 53 Case of Herrera Espinoza et al. v. Ecuador, para. 152. 54 Cf. Case of Chaparro Álvarez and Lapo Íñiguez v. Ecuador, paras. 107 and 117, and Case of Bayarri v. Argentina, para. 74, and Case of Jenkins v. Argentina, para. 85. 20