A Brazilian diplomat revealed Monday that he helped a Bolivian opposition senator escape to Brazil after he was holed up for 15 months in Brasilia\'s embassy in La Paz. Senator Roger Pinto, an opponent of Bolivian President Evo Morales, made his escape Friday in an embassy car escorted by Brazilian marines, driving 22 hours to the southwestern Brazilian city of Corumba, 1,600 kilometers (1,000 miles) from La Paz. \"I chose life. I chose to protect a person, a persecuted politician, like (Brazilian) President Dilma (Rousseff) was persecuted,\" Eduardo Saboia, the Brazilian charge d\'affaires in La Paz, told Globo television on his arrival in Brasilia, where he was recalled for consultations. The diplomat said he took the personal decision to help Pinto escape \"because there was an imminent threat to the life and dignity of the senator.\" He said Pinto was suffering from depression and was contemplating suicide. In La Paz, Bolivian Foreign Minister David Choquehuanca expressed \"profound concern over the transgression of the principle of reciprocity and international courtesy.\" \"Under no condition could Senator Pinto leave the country without a safe conduct pass,\" Choquehuanca said. Pinto, who flew from Corumba to Brasilia on Sunday, had not been granted safe conduct even though he received political asylum a year ago. In a letter released by his right-wing National Convergence party in La Paz on Monday, Pinto said he owed his freedom to Brazil. In the two-page missive, the senator thanked all those who made his escape possible and expressed gratitude to Rousseff for granting him asylum in May 2012. Pinto also praised Marcel Biato, who was Brazil\'s ambassador in La Paz until June and who \"protected me and offered security and shelter.\" Biato was transferred in June and has yet to be replaced. Pinto also hailed Saboia as \"a brave and intelligent man, who knowingly took the risk of conducting a dangerous mission.\" \"My exit is proof to Morales that good prevails in the end,\" the senator said in his \"Open letter to the Bolivian people,\" railing against \"the violation of human rights in Bolivia.\" Pinto said he would continue speaking out against \"narcotrafficking, corruption, (and) abuse of power in Bolivia,\" as well as \"against the humiliation of Bolivians\" who do not share Morales\'s views. The Brazilian foreign ministry said Sunday it was investigating how Pinto was able to leave the embassy and would take appropriate measures. Bolivian Interior Minister Carlos Romero said there was little that could have been done to stop Pinto if he was taken out of the country in an embassy vehicle. \"A diplomatic vehicle cannot be subject to any kind of search at any checkpoint. It\'s part of the sovereign jurisdiction of the country in question, in this case Brazil,\" Romero said. Saboia said the Bolivian dissident \"spent 452 days in a cubicle next to my office.\" \"There was a constant violation of human rights because there was no prospect for an exit, there was no negotiation and (Pinto) was suffering from depression, which was worsening,\" the diplomat added. \"We had to call a doctor and he was beginning to speak of suicide.\" The Bolivian government views Pinto as a fugitive from justice after he was accused of corruption, for which he was sentenced to a year in prison. He sought refuge at the Brazilian embassy last year, claiming to be a victim of political persecution after he denounced alleged cases of corruption and alleged links between authorities and drug traffickers. His case strained relations between La Paz and Brasilia. Morales last year said Brazil\'s decision to grant Pinto asylum was \"a mistake.\" Late Sunday, Bolivian Communications Minister Amanda Davila formally asked Brazil to provide information about the case, although she insisted the affair \"would not affect\" bilateral ties.