‘I always hear them before I see them’: Drones strike fear in Colombia

Attacks and surveillance According to analysts, armed groups are using the aerial devices primarily for two purposes: attacks and surveillance. "They target certain infrastructure, attack police and attack the army," Bonilla said. "But another very common use is territorial control through surveillance flights." She points to the use of drones to survey farmland seeded with coca, the key ingredient for cocaine and a key source of revenue for armed groups. …