Iran carried out its first known execution Thursday over the protests that have shaken the regime since September, hanging a 23-year-old man after a legal process denounced as a show trial by rights groups. Mohsen Shekari was convicted and sentenced to death for blocking a street and wounding a paramilitary during the early phase of the protests in mid-September. At least a dozen other people are currently at risk of imminent execution after being sentenced to hang over the protests in recent weeks, human rights groups warned.