121. In said report, the Commission considered that this provision “contravenes the Convention” since “it leaves the decision as to the appropriateness of the arrest to the subjective judgment of the police officer carrying out the arrest.” The Commission understood that the requirement for a statutory description of a crime in order to restrict personal liberty, “is not satisfied by a vague and general prescription such as ‘serious presumption of responsibility.´”102 122. The Commission concludes that: i) the State has not provided an explanation regarding the specific legal grounds under which the arrests were conducted indiscriminately in violation of provisions of the law; and ii) if the basis for the arrests was the serious presumption of guilt, the Commission reiterates that said provision is in and of itself inconsistent with the principle of legality as it pertains to personal liberty. Based on the foregoing, the Commission finds that the State of Ecuador violated the right not to be deprived unlawfully of liberty, as established in Article 7.2, in connection with the obligations set forth in Articles 1.1 and 2. Of the American Convention, to the detriment of the victims of the case. 2. Pretrial detention 123. The Court has ruled that preventive or pretrial detention is limited by the principles of legality, the presumption of innocence, need and proportionality, all of which are strictly necessary in a democratic society.103 It has also held that it is a precautionary rather than a punitive measure 104 and that it is the most severe one that could be imposed on a defendant and, therefore, it should be used as on an exceptional basis. In the view of the Court, the rule must be the defendant’s liberty while a decision is being made regarding his criminal responsibility. 105 The Court has emphasized that particular circumstances of the alleged perpetrator and the seriousness of the offense he is charged with are not, in and of themselves, sufficient grounds for preventive detention.106 124. As for the reasons to warrant preventive detention, the bodies of the system have construed Article 7.3 of the American Convention to the effect that evidence of responsibility are an essential requirement but insufficient on their own 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. 107 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 can only be 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.”108 102 IACHR, Merits Report 66/01.Case 11.992 Dayra María Levoyer Jiménez (Ecuador), June 14, 2001, para. 37. IA Court of HR, Case of López Álvarez. Judgment of February 1, 2006. Series C No. 141, para. 67; Case of García Asto and Ramírez Rojas. Judgment of November 25, 2005. Series C No. 137, para. 106; Case of Palamara Iribarne. Judgment of November 22, 2005. Series C No. 135, para. 197; and Case of Acosta Calderón. Judgment of June 24, 2005. Series C No. 129, para. 74. 103 104 IA Court of HR, Case of Suárez Rosero v. Ecuador. Judgment November 12, 1997. Series C No. 35, para. 77. 105 IA Court of HR, Case of López Álvarez. Judgment of February 1, 2006. Series C No. 141, para. 67; Case of García Asto and Ramírez Rojas. Judgment of November 25, 2005. Series C No. 137, para. 106; Case of Palamara Iribarne. Judgment of November 22, 2005. Series C No. 135, para. 196; and Case of Acosta Calderón. Judgment of June 24, 2005. Series C No. 129, para. 74. 106 IA Court of HR, Case of López Álvarez. Judgment of February 1, 2006. Series C No. 141, para. 60; Case of García Asto and Ramírez Rojas. Judgment of November 25, 2005. Series C No. 137, para. 106; Case of Palamara Iribarne. Judgment of November 22, 2005. Series C No. 135, para. 196; and Case of Acosta Calderón. Judgment of June 24, 2005. Series C No. 129, para. 75; and Case of Tibi. Judgment of September 7, 2004. Series C No. 114, para. 180. 107 IA Court 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 v. Honduras. Merits, Reparations and Costs. Judgment of September 21, 2006. Series C No. 152, para. 90. 108 IA Court 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. Continúa… 30