On the morning of Dec. 1, 2007, Alfred J. Chavez, a U.S. Army Corps of Engineers Park Ranger, noticed someone had tampered with a lock and chain on the gate of a Corps-owned pump house near Abiquiu Lake. As Mr. Chavez investigated, two men left the pump house. One of the men pulled out a revolver and fired two shots at Mr. Chavez. One bullet whizzed by Mr. Chavez's head, but the other struck him just above the right knee. The men fled and have not been apprehended. Mr. Chavez survived.