However , Defense Department officials said the man was an imposter with a history of impersonating American POWs .
The 2013 Canadian documentary Unclaimed told the story of an elderly man in Vietnam claiming to be a U.S. soldier thought killed in action in 1968 .
Defense Department officials said the man was an imposter with a history of impersonating U.S. POWs .
The 2013 Canadian documentary Unclaimed told the story of an elderly man in Vietnam claiming to be a U.S. soldier thought killed in action in 1968 .