Why Not Bomb Las Vegas?

Found in Mike Shayne Mystery Magazine, v20 #5, April 1967.
At a sporting event in a small city, remote controlled small drones attack with explosives, killed dozens and frightening the citizenry. Another attack soon thereafter creates almost a ghost town. The Bureau is after who is behind it and since newcomer Desiree Fleming was actually at the first event, she is literally and figuratively in the middle of things.