The kaleme site reported late Tuesday that 20-year-old Mohammad Amin Valian had testified he threw stones at security forces and plainclothes pro-government militiamen as they "savagely" beat demonstrators during the rally in Tehran.
Valian was found guilty of Moharebeh — a religious offense that translates as defiance of God, a crime punishable by death under Iranian law.
So far, Iran has executed two people and sentenced 11 others — including Valian — to death for taking part in opposition protests that have challenged President Mahmoud Ahmadinejad's proclaimed election victory.