Sometime during the night of July 9th, a thief or thieves broke into the parkâs visitor center/museum and removed artifacts associated with the James H. Cook Collection from the exhibit hall. The crime scene was processed by the Nebraska State Patrol with assistance from park rangers. The vast majority of the Cook Collection of Plains Indian artifacts is intact and was unaffected by the burglary. The visitor center was temporarily closed to facilitate the investigation but has reopened with only the affected exhibit area remaining closed to the public. The investigation continues.