Iranian state television has shown a video in which a champion wrestler facing two death sentences appears to confess to killing a water company security guard during anti-government protests in 2018.
The case of wrestler Navid Afkari, 27, has caused an outcry from Iranians and human rights groups.
US President Donald Trump on Thursday called on Iran not to execute Mr Afkari.
According to the Centre for Human Rights in Iran, Mr Afkari and his brother Vahid were arrested in Shiraz on September 17, 2018, while another brother, Habib, was arrested three months later. They were charged with “waging war against the state, corruption on earth and forming anti-revolutionary group” and killing the security guard on August 2, 2018.
A provincial court in Shiraz sentenced Mr Afkari to death and his brothers Vahid and Habib to 54 and 27 years in prison, respectively, in July this year. All three were also sentenced to 74 lashes, the centre said.
State media reported in August that Iran’s Supreme Court had upheld the two death sentences against Mr Afkari.
The killing of the security guard occurred during some of the worst unrest in the country in a decade after a rise in fuel prices. Iran’s clerical rulers blamed the street protests on “thugs” linked to exiles and foreign foes – the United States and Israel.
Iranian television on Saturday showed what appeared to be written confessions by Mr Afkari, but he has said in a recording circulated on social media that he was coerced to sign the documents.
“I hit twice, once and then again,” Mr Afkari was shown saying with a stabbing gesture during a police reconstruction of the killing of the guard, who reportedly worked at the local water authority in Shiraz.
Mr Afkari’s lawyer said there was no clear evidence proving his client’s guilt.
“There is no picture of the moment of the crime. The alleged video is from an hour before the murder,” Hassan Younesi said on Twitter.
Iran’s state media often air purported confessions by suspects in politically charged cases.
The International Federation for Human Rights and London-based Justice for Iran said in a report in June that Iranian state media have aired more than 355 forced confessions in the past decade.
Iran systematically used forced confessions to “instil fear and repress dissent”, according to the report.
Iranian officials reject such accusations.