As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AMA- FLIGHT 3808 ON TAKEOFF THE CREW NOTED SMOKE IN THE LAV AND RETURNED TO AMA WITHOUT INCIDENT. MAINTENANCE PERFORMED A OPERATIONAL CHECK OF THE LAV FIRE DETECTION SYSTEM AND CHECKED THE LAV FOR SMOKE, NO DEFECTS NOTED. COULD NOT DUPLICATE THE PROBLEM AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.