As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR RETURN DUE TO SMOKE SMELL IN CABIN AND AFT LAV SMOKE DETECTOR SOUNDING. INSPECTED A/C FOR SOURCE OF SMELL. DETERMINED THAT OILY SMELL WAS COMING FROM THE LT AC PACK. DEFERRED PER MEL 21-1. INSPECTED AFT LAV AREA AND NO EVIDENCE FOUND. DISCONNECTED DETECTOR AND DEFERRED PER MEL 26-16.