Mike Shockley is used to working alone. Until recently, the Bureau of Indian Affairs police officer was one of just two assigned to night patrols in a tiny police department of six officers and two investigators based on the Wind River Indian Reservation. The 2.2-million-acre reservation, a breathtaking expanse of prairie rising to central Wyoming's snowy Wind River Mountains, is home to 7,500 members of the Northern Arapaho and the Eastern Shoshone tribes.