A Mount Rainier National Park ranger was fatally shot following a New Year's Day traffic stop, and the 368-square-mile park in Washington state was closed as dozens of officers searched for the armed gunman over snowy and rugged terrain.

Pierce County Sheriff's spokesman Ed Troyer said late Sunday afternoon Benjamin Colton Barnes, a 24-year-old believed to have survivalist skills, was a "strong person of interest" in the slaying of Margaret Anderson. A parks spokesman said Barnes was an Iraq war veteran, and the mother of his child had alleged he suffered from post-traumatic stress following his deployments. Authorities recovered his vehicle, which had weapons and body armor inside, Troyer said.

Barnes was also a suspect in the early Sunday morning shooting of four people at a house party south of Seattle, reports the Associated Press.