LEFT VEHICLE UNATTENDED, OFF AND LOCKED FOR APPROXIMATELY 20 MINS. WHEN I RETURNED THE VEHICLE WAS SMOKING OUT OF THE HOOD VENTS NEAR THE WINDSHIELD. CALLED 911 AND DISCONNECTED THE BATTERY. WHEN 1ST RESPONDER ARRIVED VEHICLE WAS ON FIRE. PRIOR TO THIS I THOUGHT I HAD HEARD A MOTOR RUNNING WHILE DRIVING TO THE LOCATION, WHICH SEEMED UNUSUAL BUT IT WAS A WARM DAY AND I PASSED IT OFF AS A COOLING FAN AND I LISTENED TO THE VEHICLE AFTER ARRIVAL AND EVERYTHING SEEMED OFF AND QUITE, IE. NORMAL. VEHICLE IS CURRENTLY AT DEALERS AWAITING INSPECTION BY BMWNA BEFORE ANY REPAIRS WILL BEGIN. VIN AND PAPERWORK IN VEHICLE APPROX 120 MILES AWAY. MODEL IS 330CI. *NM