The four activists are Hadi Heydari, a cartoonist for Iranian reformist papers; Mohammad Shafiei and Ali Reza Taheri, members of the youth branch of the Islamic Iran Participation Front; and Fatemeh Arabsorkhi, daughter of jailed leading reformist Feizollah Arabsorkhi.
The reason for their detention on December 20 has not yet been made public.
Fatemeh Arabsorkhi’s sister, Sajedeh, told Radio Farda that Fatemeh has said that she is being held in solitary confinement in Evin prison. Sajedeh said Fatemeh suffers from heart disease and has been hospitalized several times in recent months. She suggested that the security forces may have arrested Fatemeh in order to compound the pressure on their father.
Feizollah Arabsorkhi is a senior member of the Islamic Revolution Mojahedin organization who was arrested shortly after the disputed June 2009 presidential election and is currently serving a six-year jail term in Evin prison.
In August 2010, Feizollah Arabsorkhi, together with six other reformist figures, filed a complaint against the commanders of the Islamic Revolutionary Guard Corps for their interference in the election.
Listen to the story in Persian here.