As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT THE AFT SMOKE DETECTOR ALARM SOUNDED AND PASSENGERS SMELLED ODD ODOR IN REAR OF ACFT. FLIGHT CREW RETURNED ACFT TO DEPARTURE AIRPORT. MX FOUND OIL LEAKING FROM THE APU AREA AND REPLACED THE APU IAW AMM. PERFORMED OPN 5089 DUCT BURNOUT AND REPLACED COALESCER BAGS.