Is it in fact the notorious American gangster John Dillinger who lies buried in an Indiana cemetery?
He escaped from jail three times, stole submachine guns from police armories, and fashioned a well-earned reputation as "Public Enemy Number One."
"If he was not killed on that date, I am interested in discovering what happened to him, where he lived, whether he had children, and whether any such children or grandchildren are living today."
The agency's Chicago office tweeted that "a wealth of information supports Dillinger's demise."
The notion that it was a Dillinger Doppelganger who died instead, the FBI said, was a "conspiracy theory."