As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS MUSTY ODOR IN CABIN AND COCKPIT WITH EXTERNAL AIR OR WITH AIRCRAFT A/C SYSTEM ON GROUND AND IN FLIGHT. MAINTENANCE DETERMIND THE SOURCE TO BE FROM THE APU. MAINTENANCE REPORTS AFTER FURTHER BURNOUT AND INSPECTION IAW JOB CARD 26L00021004, FOUND CABIN ODOR TO CLEAR AND APU OK FOR SERVICE. COMPLETED JOB CARD 26L00021004 AS REQUIRED. NO LEAKS OR DEFECTS NOTED.