Revelations that protesters detained in Iran's post-election crackdown were tortured, some to death, were a deep embarrassment to the country's clerical rulers. Dr. Ramin Pourandarjani was pressured to change the death certificate of one of the most well known victims and later spoke to a parliament commission investigating the abuse, opposition Web sites reported. Much of the abuse took place at a facility known as Kahrizak on Teheran's outskirts, where Pourandarjani - a general practitioner - was the only doctor, serving there once a week as part of his mandatory military service. Deaths of several protesters in custody raised outrage among the opposition and even among some conservatives who support Iran's government. Hundreds of protesters and opposition activists were arrested in the crackdown that suppressed protests following the disputed June 12 presidential election. The opposition says at least 69 people were killed while the government has confirmed around 30 deaths. More than 100 protesters, activists and pro-reform opposition have been on trial, accused of fueling the protests and being part of a plot to overthrow the government. On Tuesday, the Justice Ministry announced that so far five people have been sentenced to death in the trial and 81 others have been sentenced to prison terms ranging from six months to 15 years. Pourandarjani's death on Nov. 10 was first reported by the opposition Web sites and later confirmed by Iranian authorities. Hanif Mazroui, a reporter for the opposition news Web site Roozonline, said he was contacted by a doctor earlier this week who told him Pourandarjani had committed suicide. The doctor, a colleague of Pourandarjani, later called Mazroui back and said the cause of death was "suspicious, and (authorities) are not making it public," Mazroui told The Associated Press. At first, authorities announced that Pourandarjani had a heart attack in his sleep. Then they claimed he died of poisoning. Late Monday, the office of Teheran's general prosecutor Abbas Dowlatabadi said "preliminary autopsy revealed he did not die of poisoning." Dowlatabadi ordered investigations to continue, and his office said the cause will be announced later. The doctor's father, Reza-Qoli Pourandarjani, said he didn't believe any of the causes given so far by the government in his son's death. But he didn't go as far as accusing authorities of killing his son. "Just the night before his death, my child talked to me on the phone, it was around 8 or 9 p.m. He sounded great, very dignified, displaying no sign of someone about to commit suicide," the senior Pourandarjani said in a telephone interview from his home in Tabriz in northwestern Iran. "He was even full of hope," and making plans with friends, the father said. The next day, the elder Pourandarjani received a call from the commander of Teheran's security forces informing him that his son was in a car accident with a broken leg and needed his consent to have surgery. When he traveled to Tehran, "we found out that that wasn't the case," the father said. The body was handed over to the family, and was buried in Tabriz on Sunday, but the father said he never saw the body because he was too grief-stricken. "Our son was part of Iran's elite. He had done his studies. He was finishing his military service. He was a general practitioner and wanted to specialize," he said in a heavy voice. Several opposition Web sites raised concerns that Pourandarjani was killed because he knew the conditions of a number of torture victims at Kahrizak, including 24-year-old Mohsen Rouhalamini, the son of a prominent conservative figure. Rouhalamini's death in late July was the main factor raising anger among government supporters over the abuse. According to the opposition Web site, Pourandarjani was detained for a week until he agreed to announce the cause of Rouhalamini's death as meningitis rather than from beatings. Pourandarjani also was interviewed by the parliamentary committee investigating the abuse, according to Mazroui. The Kahrizak detention facility was used to keep a large number of detainees during the early days of the mass protests that erupted against the re-election of President Mahmoud Ahmadinejad, which the opposition said was fraudulent. Amid the anger over allegations of torture, Supreme Leader Ali Khamenei ordered the facility's closure in July, saying it did not meet standards.