As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED SMOKE IN CABIN. RETURNED TO DEPARTURE AND LANDED WITHOUT INCIDENT. FOUND AUXILIARY POWER UNIT (APU) OIL LEAKAGE WITH POSITIVE INDICATIONS OF INGESTION INTO APU INTAKE. REPLACED APU AND PERFORMED PACK BURN. SYS GROUND CHECKED NORMAL OPERATION. (K)