A middle-aged Japanese recently pleaded guilty to a strange crime: attempting to sell “weapons-grade plutonium” acquired in Myanmar to an Iranian general. Unfortunately, for the gangster, the “Iranian” was a fictitious character invented by DEA agents. The guy will likely disappear into the American prison system for life — but a huge mystery still surrounds his case: how did he cop “weapons-grade” plutonium in Myanmar, a poor country with no known enrichment facilities? The World’s Patrick Winn reports.