As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 3771 - FWA-MCI - DURING CRUISE, THE APU FIRE BELL AND LIGHT CAME ON. PERFORMED CHECKLIST, DECLARED AN EMERGENCY, AND DIVERTED TO MLI. THE AIRCRAFT LANDED AT MLI WITHOUT ANY FURTHER DIFFICULTIES. DEFERRED THE APU FIRE DETECTION SYSTEM PER KHA B727 MEL. THE AIRCRAFT WAS RETURNED TO SERVICE. (M)