During a weather briefing before takeoff, the pilot was advised of flight precautions for turbulence, IFR conditions, and icing. While en route at 12,000 ft, the pilot reported that he was picking up rime ice. He was cleared to 11,000 and then 10,000 ft. When he was unable to maintain that altitude, he was advised to descend further to 9,000 ft and reverse course. The last communication was from a female stating they were in trouble, losing airspeed fast, and were going into the mountains. Witnesses heard the aircraft, then saw it come out of the clouds and crash at an elevation of 3,300 ft. About 20 to 30 seconds after the primary impact, the left V-tail stabilizer fell to the ground about 1,000 ft from the main wreckage. Also, the right cabin door and the baggage door were found away from the main wreckage. An examination of the stabilizer revealed it had separated downward. Mountain tops in the area were up to 6,956 ft.