They are Chechens. The father fought in the Chechen war and was beaten by the Russians for his participation. The youngest son was not born in Chechnya, though. According to the Maryland uncle, the white hat was born near by, but not in Chechnya. Interestingly, the relative of the hospitalized Saudi person of interest also fought in those Chechen wars against the Russians, leaving Chechnya sometime after the bombing of the twin towers, when he met up with Osama Bin Laden.