[…] b) prior notification in detail to the accused of the charges against him; c) adequate time and means for the preparation of his defense; […] f) the right of the defense to examine witnesses present in the court and to obtain the appearance, as witnesses, of experts or other persons who may throw light on the facts; […] 113. The petitioner alleged that, during the criminal proceedings that resulted in his conviction, he was denied several of the fair trial rights provided for in the Convention. The IACHR examines those allegations below. a) Presumption of innocence and illegitimacy of the precautionary measure restricting foreign travel 114. The presumption of innocence is one of the main pillars of criminal procedure that underlies the purpose of fair trial rights. It means that a person cannot be convicted unless there is clear evidence of his criminal liability. If the evidence presented is incomplete or insufficient, he must be acquitted.145 The relationship between the presumption of innocence and the precautionary measure of prohibiting the defendant from leaving the country was addressed specifically by the bodies of the Inter-American System in the Case of Ricardo Canese v. Paraguay. It that judgment, the Inter-American Court held that the restriction of foreign travel cannot be a substitute for the penalty or be used to meet its objectives. This can happen if the measure is used beyond what is strictly necessary to ensure the defendant’s appearance at trial, in which case it becomes in practice a sort of advance sentence. In the Court’s opinion, these measures are contrary to the presumption of innocence provided for in Article 8.2 of the Convention and the right to freedom of movement established in Article 22 thereof.146 115. The right to freedom of movement, including the right to leave one’s own country, may also be subject to restrictions. According to Articles 22.3 and 30 of the American Convention, any such restrictions must meet the following requirements: a) they must be expressly established by law; b) they must be designed to prevent crime or to protect national security, public safety, public order, public morals, public health, or the rights or freedoms of others; and c) they must adhere to the principle of proportionality. 116. As noted earlier, on December 16, 2004, the Seventh Trial Court issued an order barring Tulio Álvarez from leaving the country, based on Article 256(4) of the Organic Code of Criminal Procedure, which establishes that: “Provided that the grounds for pretrial detention can be reasonably satisfied through the use of another measure less burdensome to the defendant, the competent court, on its own motion or at the request of the Public Ministry or of the defendant, shall instead impose, through a well-reasoned decision, one of the following measures: […] 4. The prohibition against unauthorized travel outside the country, the local district in which the defendant resides, or the geographical area identified by the court.” 117. It is not sufficient, however, for the measure to be established in a law. Because they are precautionary rather than punitive measures, they must be applied on an exceptional basis, respecting the presumption of innocence and the principles of necessity and proportionality imperative in a democratic 145 I/A Court H.R., Case of Cantoral Benavides v. Peru. Merits. Judgment of August 18, 2000, paras. 119-120; I/A Court H.R., Case of Ricardo Canese v. Paraguay. Merits, Reparations and Costs. Judgment of August 31, 2004. Series C No. 111, para. 153; Case of Cabrera García and Montiel-Flores v. Mexico. Preliminary Objection, Merits, Reparations, and Costs. Judgment of November 26, 2010, para. 183; Cfr. Case of Suárez Rosero v. Ecuador. Judgment of November 12, 1997. Series C No. 35, para. 77. 146 I/A Court H.R., Case of Ricardo Canese v. Paraguay. Merits, Reparations and Costs. Judgment of August 31, 2004. Series C No. 111, para. 129.