As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT ATTENDANT'S REPORTED THAT THE CABIN HAS A BAD ODOR SMELL THAT WAS CONSTANT THROUGHOUT THE FLIGHT.. MAINTENANCE FOUND THE APU COMPARTMENT WAS SOAKED IN OIL DUE TO THE APU OIL CAP BEING OFF / LOOSE AND SECURED IT AS REQUIRED.