As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR RETURN - FLIGHT 5134 - ENROUTE FROM LBF TO DEN PILOTS REPORTED SMOKE/MIST IN THE CABIN AFTER DEPARTURE. MAINTENANCE TROUBLESHOT THE ISSUE AND FOUND NO SMOKE, HOWEVER, MIST WAS WAS REPORTED AND MAINTENANCE FOUND AN EXCESSIVE AMOUNT OF MOISTURE IN THE AIR CYCLE MACHINE. MAINTENANCE REMOVED MOISTURE PERFORMED A SYSTEM OPERATIONAL CHECK. REFERENCE 1900D MM 21-50. OPERATIONAL CHECK GOOD.