WHILE DRIVING A BURNT PLASTIC SMELL WAS PRESENT. WAS UNSURE IF THE SMELL WAS COMING FROM INSIDE OR OUTSIDE THE VEHICLE. PARKED VEHICLE, TURNED OFF IGNITION, LEFT VEHICLE OUT OF SIGHT FOR AN ESTIMATED 5 MINUTES, VEHICLE WAS STATIONARY FOR THE REST OF INCIDENT. UPON RETURN TO THE VEHICLE THE REAR CARGO AREA WAS FILLING WITH SMOKE. SMOKE APPEARED TO BE GENERATING FROM THE REAR DRIVER SIDE CARGO AREA, BEHIND THE 3RD ROW SEATS. ENTERED VEHICLE, REMOVED PERSONAL ITEMS, ATTEMPTED TO OPEN REAR CARGO HATCH AND HATCH WOULD NOT OPEN. AT THIS POINT THE SMOKE HAD COMPLETELY FILLED THE INTERIOR CABIN AND FLAMES ENGULFED THE VEHICLE. THE INTERIOR WAS COMPLETELY BURNED UP.