Sierra was an Iranian operative in the late 70's.  Shown here with the American Hostages taken form the US Embassy.  What role he played in the Iranian Revolution may never be fully known.

Sierra was believed to be very close to the Ayatollah Khomeini.  Seen here departing Khomeini's private jet, Ruben was given the nickname "Irene Hendershot" by his Iranian friends.  What devious meaning lay behind that name is unknown.