Iran has executed Mohammad Salas, a Sufi minority order member, who it had convicted earlier of killing three police officers and two security guards during a protest in February.
Amnesty International condemned the execution on Monday, saying the trial of Salas was grossly unfair. There had been public outcry over the conviction of the Sufi Muslim man after he had said he wouldn't have been able to even kill an ant.
The uproar over the death penalty had intensified after it was reported that witnesses said someone else, not Salas, was at the wheel of the bus when it rammed into the police.
Iran's Sufi Muslims are persecuted and the sect is banned in the country. The majority Shia sect considers the Sufis as a direct threat to them.
"I cannot even kill an ant", Salas was quoted as saying by Iran Human Rights Monitor.
Salas belonged to Iran's largest Sufi order, the Nemattolah Gonabadi community. Amnesty said the Salas' case laid bare the flaws in Iran's criminal justice system and that a huge miscarriage of justice was in sight.
The rights group said the sole piece of evidence against Salas was a "confession" allegedly made under duress. Salas had retracted the confession later and said his "conscience was clear".
Salas, a bus driver, was arrested on 19 February outside a police station when his community was peacefully protesting against the persecution of the Gonabadi dervish community. He was allegedly beaten up and he police threatened that he would be beaten until he dies, the group said.
During the trial Salas was not allowed to hire a lawyer of his choosing though his family had arranged for one.
Iran allegedly persecutes the Gonabadi Dervish community members. The official Shia sect says the dervishes follow false mysticism. However, Gonabadi Dervishes consider themselves to be Shi'a Muslims. "They are Sufis who describe Sufism as neither a religion nor a sect, but rather a way of life by which people – from any religion – may find God," Amnesty report said.
Consequently, Gonabadi Dervishes have faced discrimination, harassment, arbitrary arrest and detention, imprisonment and flogging sentences, and attacks on their sacred or important sites, the rights group adds.