Unmanned aircraft from an Air Force base in North Dakota help local police with surveillance, raising questions that trouble privacy advocates. Armed with a search warrant, Nelson County Sheriff Kelly Janke went looking for six missing cows on the Brossart family farm in the early evening of June 23. Three men brandishing rifles chased him off, he said. Janke knew the gunmen could be anywhere on the 3,000-acre spread in eastern North Dakota. Fearful of an armed standoff, he called in reinforcements from the state Highway Patrol, a regional SWAT team, a bomb squad, ambulances and deputy sheriffs from three...
