What was found
SMELL OF SMOKE IN COCKPIT AND CABIN, VISIBLE FUMES REPORTED TO BE SEEN BY PASSENGERS FROM AN UNKNOWN LOCATION IN THE CABIN DURING DESCENT. DECLARED EMERGENCY, LANDED WITHOUT INCIDENT. PERFORMED FIM TASK 21-20-00-810-801A AND FIM TASK 21-20-00-810-803A. CANNOT DUPLICATE, OPS CHECK GOOD ALL SYSTEMS.