As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 7540 IAD TO BDL, CREW REPORTS WHILE DEPLANING PAX SMOKE FILLED THE CABIN FROM UNDER THE FLOOR MID-CABIN. CAPT HAD GPU REMOVED AND BLEW BOTH ENGINE FIRE BOTTLES. THERE WAS NO INDICATION OF ENGINE FIRE, NO FIRE WAS FOUND. OCM FOUND THE EPM IN THE LICC BURNED.