The Obama administration on Thursday stepped up calls for
Iran to release three American hikers and said they should receive the
same treatment as an Iranian scientist allowed to return home from the
United States.
The department also urged Iranian authorities to be forthcoming with
information about the fate of an ex-FBI agent last seen in Iran in 2007.
1 Comments in Response to US ties scientist's Iran return, US hikers' fate
And for the other side of why he went (was sent) back:
http://www.csmonitor.com/USA/2010/0715/Iran-nuclear-defector-Three-reasons-he-might-have-gone-back