The Iranian authorities must investigate the circumstances that led to the death of a blogger in detention in the capital Tehran, Amnesty International has urged amid reports he was tortured in custody. Sattar Beheshti, 35, was arrested by men believed to be from Iran's Cyber Police on 30 October at his home in Robat Karim, southwest of Tehran. On November sixth, his family members were told to collect his body from Tehran's Kahrizak detention facility, and he was buried the following day, Amnesty said in a press release here last night. The exact time and cause of his death are still unknown, but a complaint he apparently lodged with prison authorities before his death stated that he had been beaten, lending credence to reports that he died as a result of torture in detention last week, the human rights group said. "Fears that Sattar Beheshti died as a result of torture in an Iranian detention facility, after apparently lodging a complaint about torture are very plausible, given Iran's track record when it comes to deaths in custody," said Ann Harrison, Amnesty International's Deputy Middle East and North Africa Programme Director. "The Iranian authorities must immediately carry out an independent investigation into his death, including whether torture played a part in it. Anyone found responsible for abuses must be brought to justice in proceedings meeting international fair trial standards, without resort to the death penalty." Beheshti, who was not particularly well-known among Iranian bloggers, maintained a site called My Life for My Iran, on which he criticized the Iranian government. The day before his arrest, he had complained about receiving a threat because of his blog posts: "They sent me a message saying, 'Tell your mother she will soon be wearing black because you don't shut your big mouth'." Once in custody, Beheshti was reportedly detained at Kahrizak detention centre before being moved to Tehran's Evin prison, where he filed a complaint against his interrogators. In the complaint, which has been made public, the blogger stated that he had been arrested without an arrest warrant and that his interrogators had tortured him - including by tying him to a table and kicking him in the head, although it is not clear where the alleged torture happened. Media reports have suggested that when in Evin Prison, he had injuries consistent with having been hung by his wrists from the ceiling and spent some time in the prison clinic before being transferred to an unknown location on the evening of November, first. Former prisoners held at Tehran's Evin Prison confirm that torture and other ill-treatment are routinely carried out in some sections of the facility. Previous cases of death in custody have not been fully investigated in independent and impartial proceedings, Amnesty noted.