As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GNDED. EMER DECLARED, LANDING UNEVENTFUL & ACFT NOT OVERWEIGHT. DURING DESCENT RECEIVED A FIRE WARNING DETECTION FROM FIRST CLASS LAVATORY. NO SMELL NOTED. SMOKE, HAZE & POWDER OBSERVED WHEN LAVATORY DOOR OPENED. ACCOMPLISHED EXTENSIVE TROUBLESHOOTING & THOROUGH EXAMINATION OF FIRST CLASS LAVATORY. NO FAULTS OR ABNORMALITIES NOTED.