As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT SMOKE IN MID AND AFT CABIN SMOKE ALARMS WENT OFF, RETURNED TO LGA. FOUND APU INLET CONTAMINATED WITH OIL. RAN APU SEVERAL TIMES TO INSPECT FOR LEAKS. NO LEAKS FROM APU COMPONENTS FND OIL LEAKING AT FWD POSITION OF APU DOOR. SUSPECT INTERNAL APU LEAK. APU WILL BE PLACED ON MCO. PERFORMED OP 5088 AND OP 5089.