A tale of brothers struggling with morality, religion, ideology? Or, one brother whose psychology emanated from an unbalanced family dynamic influenced the other? I believe the latter. Russia, Chechnya, Islam are peripheral to this story. Elder son coddled by an obsessed mother, who seems a bit off. Her shoplifting conviction a case in point. As her first born began to behave like an angry bully, she tried to steer him away from evil booze and drugs. He dragged his young brother into an ideological excuse for escalating a violent nature into an act.
It could have been just guns, like other recent mass murders. But, the Boston Marathon Massacre had the added firepower of bombs. Yet, it was still a plot born of psychology and not ideology. Apologies to Dostoyevsky.