As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - FLT 1442 - AFTER TAKEOFF DFW, APU FIRE LIGHT ON MFDU AND APU FIRE PANEL ILLUMINATED. FIRED APU EXTINGUISHER BOTTLE AND LIGHT EXTINGUISHED. DECLARED EMERGENCY AND RETURNED TO DFW. LANDED WITHOUT INCIDENT. NO EVIDENCE OF FIRE. REPLACED APU FIRE BOTTLE AND PLACARDED APU INOPERATIVE. SYSTEM UNDER INVESTIGATION. (X)