As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ON DESCENT NOTICED STRONG DIRTY SOCK ODOR. MAINTENANCE FOUND THE APU STARTER LEAKING OIL AND INGESTING IT INTO THE APU INLET. REPLACED APU STARTER O-RING PER AMM 49-42-51 AND ACCOMPLISHED A SATISFACTORY LEAK / OPERATIONAL CHECK.