Why was Mohammad Reza Sharifi Nia imprisoned?

Mohammad-Reza Sharifinia is an Iranian actor and film producer. 

In 1988, Iranian authorities, acting on the orders of Supreme Leader Ayatollah Khomeini, summarily and extrajudicially executed thousands of political prisoners across the country. The number of executions is not definitively known, but according to estimates from former Iranian officials and lists compiled by human rights and opposition groups, Iranian authorities executed between 2,800 and 5,000 prisoners in at least 32 cities in the country.