78. The Court and the Commission have underscored that the personal characteristics of the alleged perpetrator and the seriousness of the offense with which they are charged are not, in themselves, sufficient justification for pretrial detention.77 With respect to the reasons that may justify pretrial detention, the organs of the system have interpreted Article 7(3) of the American Convention in the sense that circumstantial evidence of guilt are a necessary condition but not sufficient alone to impose such a measure. In the words of the Court: (…) there must be sufficient evidence to allow reasonable supposition that the person committed to trial has taken part in the criminal offense under investigation.78 Nevertheless, “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 […] based on a legitimate purpose, which is: to ensure that the accused does not prevent the proceedings from being conducted or elude the system of justice.”79 79. Thus, any decision to restrict the right to personal liberty through the imposition of pretrial detention must be justified by sufficient grounds in each instance to determine if said detention meets the requirements for its application.80 80. At the same time, Article 7(5) of the American Convention imposes time limits on pretrial detention and, consequently, on the power of the State to protect the purposes pursued by the proceeding with this type of precautionary measure. As the Inter-American Court has held, “[w]hen the duration of pretrial 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.”81 The Court has indicated that even when there are reasons to keep someone in pretrial detention, the period of detention should not exceed what is reasonable.82 81. As regards the need for periodic review of the grounds for pretrial detention and its duration, the Court has stated that: pretrial detention or imprisonment should be subject to periodic review, so that it is not prolonged when the reasons that supported it no longer exist .... Whenever it appears that pretrial detention does not meet those conditions, release should be ordered, without prejudice to the continuation of the proceedings.83 82. Besides its effects on the exercise of the right to personal liberty, both the Commission and the Court have stated that improper use of pretrial detention may undermine the principle of presumption of innocence contained in Article 8(2) of the American Convention. In that connection, the Commission has underscored the importance of the criterion of reasonableness, since to keep someone deprived of liberty 77 IACHR, Report on the Use of Pretrial Detention in the Americas, OEA/Ser.L/V/II. December 30, 2013, paragraph 21; I/A Court H.R., Case of López Álvarez v. Honduras, Judgment of February 1, 2006, Series C No. 141, paragraph 69; Case of García Asto and Ramírez Rojas v. Peru, Judgment of November 25, 2005, Series C No. 137, paragraph 106; Case of Acosta Calderón v. Ecuador, Judgment of June 24, 2005, Series C No. 129, paragraph 75; and Case of Tibi v. Ecuador, Judgment of September 7, 2004, Series C No. 114, paragraph 180. 78 I/A Court H.R., Case of Barreto Leiva v. Venezuela, Merits, Reparations and Costs, Judgment of November 17, 2009, Series C No. 206. paragraph 111. 79 I/A Court H.R., Case of Barreto Leiva v. Venezuela, Merits, Reparations and Costs, Judgment of November 17, 2009, Series C No. 206. paragraph 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, paragraph 103; and Case of Servellón García et al. v. Honduras, Merits, Reparations and Costs, Judgment of September 21, 2006, Series C No. 152, paragraph 90. 80 IACHR, Report on the Use of Preventive Custody in the Americas, OEA/Ser.L/V/II. Doc. 46/13. December 30, 2013 paragraph 21. 81 I/A Court H.R., Case of Barreto Leiva v. Venezuela, Merits, Reparations and Costs, Judgment of November 17, 2009, Series C No. 206, paragraph 120. 82 I/A Court H.R., Case of Argüelles et al. v. Argentina, Preliminary Objections, Merits, Reparations, and Costs, Judgment of November 20, 2014. Series C No. 288, paragraph 122. 83 I/A Court H.R., Case of Argüelles et al. v. Argentina, Preliminary Objections, Merits, Reparations, and Costs, Judgment of November 20, 2014. Series C No. 288, paragraph 121. 14