In one Southern California city, flying drones with artificial intelligence are aiding investigations while presenting new civil rights questions. In Chula Vista, drones are already an integral part of the way the police respond to emergencies. After an emergency call comes in, officers give the drone a location, and it flies to that point on its own — before returning on its own, too. Chula Vista obtained a BVLOS waiver from the F.A.A., so the pilot and officer can fly the drone as much as three miles from its launch site. Each day, the Chula Vista police respond to as many as 15 emergency calls with a drone, launching more than 4,100 flights since the program began two years ago.