Damn, you beat me to it! My call was Boris ‘The Blade’ Yurinov, though. (Or is that supposed to be one of the brothers?)
Boris the Blade took info from his relative to obtain the diamond in question ( 83 carats). The whole movie is difficult to figure, but Boris seems remarkably like Dokovich, aka Michael Hardin ( who apparetly has a dozen alias, whoever he is.)
Hardin bit he bibby on this grift, or Obama pulled the rug out from under Hardin. We likely will never know.