As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE AFT CARGO FIRE DETECTOR WARNING SOUNDED. FIRED BOTTLE AND MADE UNSCHEDULED LANDING AT PIT. PLACARDED FIRE DETECTION SYSTEM INOPERATIVE PER MEL AND OPERATED TO STL. REPLACED THE AFT CARGO FIRE PROTECTION CEU CONNECTOR ACCOUNT CONTAMINATED.