A detained Iranian-American academic was suddenly released from a notorious Teheran prison after spending months behind bars on charges of endangering Iranian national security - allegations her family vehemently denies. Haleh Esfandiari, director of the Middle East program at the Woodrow Wilson International Center for Scholars, had been jailed in Evin prison since early May after months of interrogation. Her 93-year-old mother used the deed to her Teheran apartment to post bail, relatives said Tuesday. "I'm very happy. It was unexpected. I thank all those who made efforts to make it possible for me to go home," Esfandiari told Iranian television on Tuesday. The footage showed her walking out of the prison and meeting family members in a car on a nearby street. Mohammad Shadabi, an official at the Teheran prosecutor's office, said Esfandiari had been released on 3 billion rials bail (about US$333,000), but he could not say whether she would be allowed to leave Iran.