...an investigator who has spent the past three years tracking down rocket-propelled grenades in Syria, AK-47-style rifles in Mali, and hundreds of other weapons that have found their way into war zones...
...ISIS could not buy in sufficient quantities. Some they looted from the Iraqi or Syrian governments, but when those ran out they did something that no terrorist group has ever done before and that they continue to do today: design their own munitions and mass-produce them using advanced manufacturing techniques...