Their identities are secret. They work after sundown, preferring deserted areas of the city. No one knows where they will strike next. They target different neighborhoods each time.
Their mission is simple: to kill Islamic State militants.
Their targets never vary, but their methods do. Sometimes they use snipers to take out a militant. Sometimes they plant roadside bombs and blow up cars. Sometimes they stab their victims, sometimes strangle them.
They are Mosul’s vigilante brigades, shadowy groups of civilians turned armed assassins who risk their lives to kill Islamic State gunmen — as well as those who support them.