 FAIR: When Boris the Blade visits Vinny and Sol in the pawn shop,  Vinny holds up the diamond. In the next shot, Boris the Blade asks  Sol where the diamond is, and Sol says it is in the locked  briefcase. Vinny had time to put it there (and can be seen doing so)  and lock the briefcase, though it was admittedly not a very bright  thing to do; then again, Vinny isnt very bright.