47 effective access to communication with the consular official; and 3) the right to the assistance itself. 154. To prevent arbitrary detentions, the Court reiterates the importance of notifying the arrested person of their right to establish contact with a third party, such as a consular official, to inform them that he or she is in the State’s custody, which must be carried out in conjunction with the obligations under Article 7(4) of the Convention. When the arrested person is not a national of the State in which he or she is held in custody, the notification of his or her right to consular assistance is based on a fundamental guarantee of the access to justice and allows the effective exercise of the right to defense given that the consul may assist the detainee in various acts of defense, such as granting or hiring legal counsel, obtaining evidence in the country of origin, corroborating the conditions under which legal assistance is provided, and observing the situation of the accused while he or she is in prison.158 155. The Tribunal shall now determine whether the State informed Mr. Vélez Loor of the right to which he was entitled. From the case file before the Court, no evidence appears proving that the State had notified Mr. Vélez Loor, a foreign detainee, of his right to communicate with a consular official of his country, in order to seek the assistance contemplated in Article 36(1)(b) of the Vienna Convention on Consular Assistance. The Court considers that the State had the obligation to prove that, in the instant case, it complied with its obligation to notify Mr. Vélez Loor of the right to seek consular assistance to which every foreign detainee is entitled and not only the Embassy of Ecuador. In this respect, it is worth emphasizing that, according to the Vienna Convention, it falls upon the detainee to decide.159 156. Now, all the parties agree that, at some moment the consular authorities were informed of the fact that Mr. Vélez Loor was in the custody of the Panamanian State (supra paras. 149 and 150); however, there is still a controversy regarding the date the consulate was notified. The evidence furnished is not consistent as to the date and manner in which the Consulate of Ecuador in Panama was informed of the fact that Mr. Vélez Loor was held in custody by the State.160 The truth is that by December 5, 2010, the Ecuadorian consular mission had already instituted proceedings for the deportation of Mr. Vélez Loor.161 In this respect, Mr. Vélez Loor stated that, while he was imprisoned at La Palma Public Jail, he had an interview with immigration officials; of May 11, de 2007. Series C No. 164, para. 116. As well as other rights the person deprived of liberty is entitled to, this right "constitutes a mechanism to avoid illegal or arbitrary detentions from the very moment of imprisonment and, at the same time, ensures the individuals right to defense.” See mutatis mutandis Case of Juan Humberto Sánchez, supra note 97, para. 82; Case of Usón Ramírez, supra note 10, para. 147, and Case of Yvon Neptune, supra note 97, para. 105. 158 Cf. The Right to Information on Consular Assistance in the Framework of the Guarantees of Due Process, supra note 145, para. 86; Case of Chaparro Álvarez and Lapo Íñiguez, supra note 99, para. 164, and Case of Bueno Alves, supra note 157, para. 116. 159 In what is relevant, article 36.1.c) of the Vienna Convention on Consular Relations states that "[…] consular officers shall refrain from taking action on behalf of a national who is in prison, custody or detention if he expressly opposes such action.” 160 On the one hand, Mr. González stated that the Consulate of the Republic of Ecuador was notified, over the telephone, by the National Office of Immigration and Naturalization of the Ministry of Interior and Justice of the detention of Mr. Vélez Loor. Cf. Statement rendered by Carlos Benigno González Gómez, supra note 122, folio 3787. On the other hand, Mr. Vélez Loor sustained that “at one moment, I had the opportunity to call the Consulate of Ecuador by means of a clandestine telephone.” Statement rendered by Jesús Tranquilino Vélez Loor at the public hearing held before the Inter-American Court on August 25, 2010. Finally, Mr. Ochoa stated “[a] few days before Christmas, [w]hen I was taken to the Ecuadorian Embassy to take my fingerprints and establish my nationality, I could talk to the ambassador; [I] told her about the case of Mr. Vélez and she told me I had to talk to the Director of the Migration Office.” Statement redered before a public notary (affidavit) by Mr. Leoncio Raúl Ochoa Tapia on August 6, 2010 (case file of the evidence, volume IX, affidavits, folio 3656). 161 Cf. Note N° 3-6-3/2002 issued by the Consulate of Ecuador in Panama addressed to the Chief of Staff of the Navy of Panama on December 5, 2002 (case file of the evidence, volume VIII, annex 51 of the answer to the application, folio 3531).