Chechen? American? Immigrant? Citizen? Muslim? The Boston Marathon bombing suspects may be all of the above, but how we attempt to come to grips with the attacks allegedly perpetrated by the brothers has much to do with how we identify them. The brothers “don’t neatly fit into pre-existing boxes,” says Peter Spiro, an international law professor at Temple. “It is a very complex picture,” challenging the psychological need to “set the boundaries of the in-group and treat others differently.”