Originally from Normandy, Antonin DeHays is in his 30s, and had been living just outside Washington DC for several years.
He had been working as a historian and researcher, studying the 1944 Normandy landings and the Allied military campaign against Nazi Germany.
He was found guilty of stealing and reselling at least 291 metallic ID dog tags bearing the names of US Air Force pilots who died in service in the Second World War, along with other memorabilia and documents.
He was sentenced to 364 days in jail, ordered to do 100 hours of community service, and required to pay US $43,457 (€35,226) in damages.
The objects and ID tags - known as dog tags because of their rounded shape and chains - were found to have been stolen over several years, from the National Archives just outside Washington DC.
Mr DeHays had been working in the archives, and used his researcher identification card to request files on pilots who had died while fighting the German Luftwaffe.
He was found to have stolen the tags, as well as 130 accompanying items - including German military records, personal photos, pieces of aircraft, letters, and immunisation documents - and listed them with vivid descriptions for resale online, making tens of thousands of dollars.
One listing described the "blood, fire and fuel stains" on the metal of a dog tag, calling them "very powerful items that witness the violence of the crash".
DeHays was also found to have given some of the objects away as gifts, and even exchanged one dog tag for a chance to sit in a Spitfire fighter at a military museum.
The scheme was partly to pay for his "addiction to collecting war memorabilia", the court heard, and also a way to raise money for his dream of opening a museum one day.
At his trial, DeHays said: "At that time I saw it as a sacrifice I had to make if I wanted my dream to come true. It was irrational behavior and a lack of judgment that I regret every day.”
Joe Davis, a spokesman for Veterans of Foreign Wars of the United States, said: “He isn’t just a thief, he’s a grave robber."
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