Mercenary with US citizenship, John Christensen is detained in Slavyansk by the Donetsk People's Army:
Piece of propaganda?
http://en.wikipedia.org/wiki/Siege_of_Sloviansk
Wiki says he was part of international military observervers, he was released together with the rest OSCE mission.
http://www.liveleak.com/view?i=668_1399131016
Watch from 9:35, he says something in russian or ukrainian? Clearly not this guy.