
Born in 1961 in St. Paul, Minnesota, the grandson of the Chief of the Winnebago Native American tribe.
Enlisted in the United States Marine Corps in 1980 and entered the Marine Corps Security Battalion Guard school, a rigorous, elite training program in which he was instructed in espionage and counterespionage techniques. Was given TOP SECRET security clearance and was assigned to the U.S. Embassy in Moscow in 1984.
As part of his assignment, he signed a non-fraternization agreement, thereby promising not to engage in friendships with Soviet citizens and to report any such contacts. Lonetree apparently received undo attention because most citizens of Moscow had never seen a Native American before. Despite such attention he was described as lonely and somber and was believed to have begun drinking excessively.
Attended the annual Marine ball in November 1985 and was introduced to Violetta Seina, a 25 year old Russian woman who was an embassy employee. The two began dating soon thereafter. Was part of the the Marine unit assigned to provide security for the 1985 summit meeting between Soviet premier mikhail Gorbachev and U.S. President Ronald Reagan.
Was introduced by Violetta to her "Uncle Sasha", who in reality was a KGB intelligence officer (named Aleksiy Yefimov). Sasha recruited Lonetree to become a "friend of the Soviet Union." Lonetree eventually provided Sasha with information about the embassy and the U.S. Ambassador. Sasha also asked him to plant a "bug" in the Embassy but Lonetree allegedly refused to do, instead provided plans for the building.