You know, just because somebody buys four guns really shouldn't indicate terrorism. Maybe he's a gun collector and likes to sit in an all italian leather sofa with a glass of pinot noir and discuss the finer points between an HK-416 and an RC-P90.
Now if he bought one rifle and lots and lots of magazine clips, THEN I would suspect something's up.
I could DIIIIIIIIE! Or worse, DIIIIIIIIIIIIE!