As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT, THE APU FIRE AUDIO OCCURRED INTERMITTENTLY (EVERY 2-3 MINUTES) WITH THE APU - OFF (NOT RUNNING). NO SECONDARY OR INDICATIONS OF FIRE WERE PRESENT. CREW PERFORMED REQUIRED ACTIONS PER RFM INCLUDING CLEARING TURNS, AND ELECTED TO RTB TO HOUMA.