proceedings.320 For a measure of deprivation of liberty to be in accordance with the guarantees established in the Convention, its application must be exceptional in nature and respect the principle of the presumption of innocence, and also the principles of legality, necessity and proportionality that are essential in a democratic society.321 311. The Court has also indicated the characteristics that a measure of pre-trial detention or custody should have in order to adhere to the provisions of the American Convention: a) It is a precautionary rather than a punitive measure: it must be aimed at achieving legitimate purposes that are reasonably related to the criminal proceedings underway. It cannot become a premature punishment or be based on general or special preventive objectives that could be attributed to the punishment.322 b) It must be based on sufficient evidence: To order and maintain measures such as pre-trial detention, there must be sufficient evidence that permits the reasonable supposition that the individual subjected to trial has taken part in the unlawful act under investigation.323 The verification of this important presumption is a necessary first step in order to restrict the right to personal liberty by means of a precautionary measure, because if there is not the slightest evidence linking the individual to the wrongful act investigated, there will be no need to safeguard the objectives of the proceedings. In the Court’s opinion, the suspicion must be founded on specific facts; that is, not on mere conjectures or abstract intuitions.324 Thus, it is evident that the State must not arrest someone in order to then investigate him; rather, it is only authorized to deprive a person of his liberty when it has sufficient information to be able to bring him to trial.325 c) It is subject to periodic review: The Court has underscored that pre-trial detention should not be continued when the reasons for its adoption no longer exist. The Court has also observed that the domestic authorities are responsible for assessing the pertinence of maintaining any precautionary measures they issue pursuant to their own laws. In this regard, the domestic authorities must provide sufficient reasons to justify why the restriction of liberty has been maintained,326 and these must be based on the need to ensure that the detainee will not impede the efficient implementation of the investigations or evade the action of justice; to the contrary, it becomes an arbitrary deprivation of liberty according to Article 7(3) of the American Convention.327 The Court also emphasizes that the judge does not have to wait until an acquittal is delivered for a person who has been detained to recover his freedom, but must periodically assess whether the grounds for the measure remain, as well as its necessity and proportionality, and also if the duration of the detention has exceeded the legal and 320 Cf. Case of Suárez Rosero v. Ecuador. Merits, para. 77; Case of Usón Ramírez v. Venezuela. Preliminary objection, merits, reparations and costs. Judgment of November 20, 2009. Series C No. 207, para. 144, and Case of J. v. Peru, para. 157. 321 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 J. v. Peru, para. 158. 322 Cf. Case of Suárez Rosero v. Ecuador. Merits, para. 77; Case of Chaparro Álvarez and Lapo Íñiguez. v. Ecuador, para. 103; Case of Barreto Leiva v. Venezuela, para. 111, and Case of J. v. Peru, para. 159. 323 Cf. Case of Chaparro Álvarez and Lapo Íñiguez. v. Ecuador, para. 101 and 102; Case of Barreto Leiva v. Venezuela, para. 111 and 115, and Case of J. v. Peru, para. 159. 324 Cf. Case of Chaparro Álvarez and Lapo Íñiguez. v. Ecuador, para. 103. 325 Cf. Case of Chaparro Álvarez and Lapo Íñiguez. v. Ecuador, para. 103. 326 Cf. Case of Chaparro Álvarez and Lapo Íñiguez. v. Ecuador, para. 107; and Case of J. v. Peru, para. 163. 327 Cf. Case of Bayarri v. Argentina. Preliminary objection, merits, reparations and costs. Judgment of October 30, 2008. Series C No. 187, para. 74, and Case of J. v. Peru, para. 163. 110