Mehdi Karrubi says an `` impartial committee '' is needed to investigate alleged mistreatment of detainees . Karrubi was to run response to opponents in Monday edition , son and reporter say . Protesters outside newspaper offices clash with police , state-run Press TV reports . - The government says it will hold a referendum on the constitution by June 30. Human-rights groups accuse guards of conducting harsh interrogations .
Karrubi was to run response to opponents in Monday edition , son and reporter say . Protesters outside newspaper offices clash with police , state-run Press TV reports . - The government says it will hold a referendum on the constitution by June 30. Human-rights groups accuse guards of conducting harsh interrogations .