SEATTLE — Staff at Mount Rainier National Park gathered Tuesday to grieve the loss of a ranger fatally shot on New Year’s Day — and to wonder what led the gunman, heavily armed and carrying a bulletproof vest, to that rugged, remote spot as he fled another shooting 100 miles away.Ranger Margaret Anderson, a 34-year-old mother of two who was married to another park ranger, was shot and killed Sunday by Benjamin Colton Barnes, a 24-year-old Iraq war veteran. After searching by plane and snowshoe, investigators found Barnes dead, apparently from the cold, in a snowy creek Monday. A handgun and a rifle were near his body.The national park, which receives 1.5 million visitors a year, remained closed Tuesday and was not expected to reopen until at least Friday. Employees attended an all-staff meeting to begin dealing with Anderson’s death. Her husband was on duty elsewhere in the park when she was killed.“We’ve just been devastated by this horrific event, and we’re just not ready to reopen quite yet,” park spokesman Kevin Bacher said. “What happened here at Mount Rainier was unprecedented in the history of the park — unprecedented in the history of most national parks, which are intended to be a place of refuge. We hope we can get it back open soon so that people can return to that place of refuge.”The FBI continued processing vehicles at the crime scene Tuesday, about a mile down the road from the Paradise visitor center. Meanwhile, the King County sheriff’s office was trying to pin down details about a shooting Barnes was involved in at a party in Skyway, south of Seattle.