Here's why the feds are freaked out about a drone attack

U.S. officials sent out a warning after Venezuelan President Nicolas Maduro was attacked with explosive drones in a failed assassination attempt.
The Aug. 4 attack targeted Maduro while he was giving a speech in Caracas. He was unharmed but seven soldiers were hurt. It raised concerns worldwide that commercial drones could be used to harm people. 
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ABC News obtained a bulletin from the FBI, Department of Homeland Secur