FBI assigned to solve case of man found dead in Missouri . Two pages of his notes were found in his pocket . One of the toughest cases involved a note composed by Brian Patrick Regan , a former Air Force master sergeant convicted of attempted espionage in 2003 . FBI unit interested in cracking codes .
FBI assigned to solve case of man found dead in Missouri . Two pages of his notes were found in his pocket . FBI unit interested in cracking codes .