The Islamic Republic judicial authorities have filed three charges against the son of a mid-ranking cleric, Mehdi Karroubi, a dissident leader placed under house arrest since 2011.
"My brother, Hossein, is facing charges in two different legal cases for the recent letters our father wrote to the Islamic Republic Supreme Leader, Ayatollah Ali Khamenei, and President Hassan Rouhani," Mohammad Taqi Karroubi disclosed on Monday, January 20.
Speaking to Radio Farda, Mohammad Taqi Karroubi also said that his brother's third case was related to a letter that he signed along with 76 political activists to condemn the brutal suppression of Iranians who poured into the streets across the country last November to protest government policies.
"I have been informed that my brother is currently in solitary confinement, and under constant interrogation by the agents of the Intelligence Ministry and other intelligence organizations," Mohammad Taqi told Radio Farda, adding, "hand in hand, the interrogators are pressuring my brother to admit committing unfounded and imaginary crimes."
Hossein Karoubi, son of Mehdi Karoubi, was arrested on January 14, three days after his father called on Ayatollah Ali Khamenei to step down over the downing of a Ukrainian airliner by the military on January 8.
Hossein and Mohammad Taqi's father, twice the speaker of Majles (the Islamic Republic's parliament), has been under house arrest since February 2011.
Ayatollah Khamenei and his ultra-conservative allies have accused Karroubi, former Prime Minister Mir Hossein Mousavi (1981-89) and his political activist wife, Zahra Rahnavard, of "sedition."
Mousavi and Karroubi were the incumbent Mahmoud Ahmadinejad's primary challengers in the 2009 presidential election. The official outcome of the election, declaring Ahmadinejad's victory, triggered widespread anti-regime protests that lasted more than two years.
A vociferous opponent of Khamenei, 82-year-old Karroubi, has written several scathing letters, calling upon him to step down.
His son, Hossein, was once before sentenced to six months discretionary jail for "propaganda against the regime," in 2017 after he published a letter his father had written to president Rouhani.