The helicopter went down at about 10:30 p.m. local time in a densely populated area near a busy road, but no one was hurt on the ground.
“One of our helicopters went down and two officers were killed," Atlanta police spokesman Carlos Campos told Reuters.
Unconfirmed reports suggest that the helicopter had been flying low and hit power lines in the area. Local television channels broadcast pictures of burning debris off the road.
The missing child was later found unharmed.
Police chief George Turner said that the National Transportation Safety Board and the Federal Aviation Administration were investigating the crash.