As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT RETURNED TO LGA DUE TO SMOKE IN THE CABIN WITH LAVATORY SMOKE DETECTORS SOUNDING AFTER TAKEOFF. MAINTENANCE FOUND AN APU OIL LEAK AT THE CAP AND REPLACED IT. THE APU INLET AND EXTERNAL AREAS WERE CLEANED AND OPERATION 5089 DUCT BURN OUT PROCEDURES WERE ACCOMPLISHED. (2010-D1397) (DLM88103254)