(Zenit) – A priest sentenced to 15 years in prison for speaking out about anti-Christian persecution received a sentence reduction for “good conduct,” but some observers fear he is being drugged. The 58-year-old Father Thadeus Nguyen Van Ly, one of the country’s best-known dissidents, was sentenced by a Hanoi court in 2001, after being accused of attacking national unity. News of the reduction of the sentence was confirmed Thursday by the official Vietnam News Agency, which stated that, in addition to his “good conduct,” the priest had been very respectful of the rules of Nam Ha prison. However, sources of AsiaNews, of the Pontifical Foreign Missionary Works, in Hue said that Father Van Ly wrote and signed letters in prison praising Vietnamese socialism and the politics of the Communist Party. According to individuals who were allowed to visit him, the priest showed symptoms of mental imbalance and seemed to have been drugged as part of the effort “to re-educate him.” A Vatican delegation, led by Monsignor Piero Parolin, Vatican undersecretary for relations with states, was able to talk about the Van Ly case with Hanoi authorities during a visit to Vietnam in April. To every question posed by the delegation, government representatives showed the priest’s letters as demonstrating his “re-education.” But a Hue priest voiced skepticism. “This letter shows a 180-degree change,” he said. “We suspect that he has been drugged. Now the government is no longer afraid of him. It seems that soon, they will free him completely.” In 2001, Father Van Ly sent a letter to the U.S. Congress asking for a delay in the ratification of the bilateral trade agreement between the United States and Vietnam , citing Hanoi ‘s human rights violations and religious persecutions. The priest was arrested and sentenced to 15 years of prison. The punishment was then reduced to 10 years. Now a local court ordered the prison term to be reduced to five years, with five years of house arrest. American human rights groups consider Father Van Ly a prisoner of conscience and the U.S. government has pressured for his release. The news of Father Van Ly’s sentence reduction arrives just before a visit from European Union representatives in Vietnam for a meeting on human rights, which will also address the treatment of the prisoners.