On the morning of January 7, 2015, two masked gunmen—brothers Said and Cherif Kouachi—entered the office of French satirical newspaper Charlie Hebdo on Rue Nicolas-Appert in Paris. They had come to seek vengeance on the Charlie Hebdo staff for publishing cartoons that the brothers believed disparaged Islam and the Prophet Muhammad. By the time their rampage had ended that day, they had killed 12 people, including two police officers and a building maintenance worker, and injured nearly a dozen more. The brothers, it would later be determined, were acting on behalf of Al Qaeda in Yemen. Their weapons cache reportedly included assault rifles, machine guns, pistols, a shotgun, and a grenade launcher. The source of the brothers' rage—the radicalization of ostracized Muslim youthis one of the most uncontrollable problems in geopolitics today. The source of their arsenal, however, is more straightforward; in fact, if you shopped in Paris in the months leading up to the attacks, you may have even contributed to their weapons purchase.

Also Watch