59 There must be sufficient evidence to allow reasonable supposition that the person committed to 343 trial has taken part in the criminal offense under investigation. Nonetheless, “even in these circumstances, the deprivation of liberty of the accused cannot be based on general preventive or special preventive purposes, which could be attributed to the punishment, but can only […] be based on a legitimate purpose, which is: to ensure that the accused does not prevent the 344 proceedings from being conducted or elude the system of justice.” 244. This also entails the obligation to give sufficient reasons regarding the achievement of a legitimate purpose in line with these standards upon issuance of the preventive detention order. 345 Otherwise, it must be considered arbitrary. 245. The Principles and Best Practices on the Protection of Persons Deprived of Liberty in the Americas, approved by the IACHR further establish, under Principle III, subparagraph 2, that: […] Preventive deprivation of liberty is a precautionary measure, not a punitive one, which shall additionally comply with the principles of legality, the presumption of innocence, need and proportionality, to the extent strictly necessary in a democratic society. It shall only be applied within the strictly necessary limits to ensure that the person will not impede the efficient development of the investigation nor will evade justice, provided that the competent authority examines the facts and demonstrates that the aforesaid requirements have been met in the 346 concrete case. 246. As to the duration of preventive detention, the Court has held that Article 7.5 of the Convention guarantees the right of every person in pre-trial custody to be tried within a reasonable time or to be released without prejudice to the continuation of the proceedings. This right imposes temporal limits on the duration of pre-trial detention and, consequently, on the State’s power to protect the purpose of the proceedings by using this type of precautionary measure.347 In the words of the Court: “when the duration of the pre-trial detention exceeds a reasonable time, the State can restrict the liberty of the accused by other measures that are less harmful than deprivation of liberty by imprisonment and that ensures his presence at the trial. This right also imposes the judicial obligation to process criminal proceedings in which the accused is deprived of his liberty with greater diligence and promptness.”348 343 IA Ct of HR, Case of Barreto Leiva v. Venezuela. Merits, Reparations and Costs. Judgment of November 17, 2009. Series C No. 206. Para. 111. Citing. Case of Chaparro Álvarez and Lapo Íñiguez v. Ecuador. Preliminary Objections, Merits, Reparations and Costs. Judgment of November 21, 2007. Series C No. 170, para. 101 and Case of Servellón García et al Vs. Honduras. Merits, Reparations and Costs. Judgment of September 21, 2006. Series C No. 152, para. 90. 344 IA Ct of HR, Case of Barreto Leiva v. Venezuela. Merits, Reparations and Costs. Judgment of November 17, 2009. Series C No. 206. Para. 111. Citing. Case of Chaparro Álvarez and Lapo Íñiguez v. Ecuador. Preliminary Objections, Merits, Reparations and Costs. Judgment of November 21, 2007. Series C No. 170, para. 103; and Case of Servellón García et al Vs. Honduras. Merits, Reparations and Costs. Judgment of September 21, 2006. Series C No. 152, para. 90. 345 IA Ct of HR, Case of Barreto Leiva v. Venezuela. Merits, Reparations and Costs. Judgment of November 17, 2009. Series C No. 206. Para. 116. 346 Principles and Best Practices on the Protection of Persons Deprived of Liberty in the Americas. Principle III, st number 2. Document approved by the Commission at the 131 regular session, held from March 3 to 14, 2008. 347 IA Ct of HR, Case of Barreto Leiva v. Venezuela. Merits, Reparations and Costs. Judgment of November 17, 2009. Series C No. 206. Para. 119. 348 IA Ct of HR, Case of Barreto Leiva v. Venezuela. Merits, Reparations and Costs. Judgment of November 17, 2009. Series C No. 206. Para. 120.