What was found
CREW REPORTS, RT LAV SMOKE DETECTOR SOUNDED WHILE TAXIING TO GATE AFTER LANDING. FLIGHT ATTENDANT REPORTED FOG IN CABIN AND NO FIRE DETECTED AT THAT TIME. RAN LT AND RT ENGINES WITH PACKS ON, RAN APU AND COULD NOT DUPLICATE PROBLEM. NO FOG OR SMOKE IN CABIN. LEAK CHECKED APU AND ENGINE, ALL OK.