MARYSVILLE, Wash. - Three students fought for their lives in Seattle-area hospitals Sunday, days after being shot in the head during an attack at a high school on Washington's Puget Sound.

The close-knit community, meanwhile, on the nearby Tulalip Indian reservation struggled with the news that the shooter was a popular teenager from one of their more well-known families.

A tribal guidance counsellor said no one knows what prompted 14-year-old Jaylen Fryberg to walk into a busy school lunchroom and open fire Friday.

"We can't answer that question," said Matt Remle, who has an office at Marysville-Pilchuck High School. "But we try to make sense of the senselessness."

Churches have held vigils since the attack that killed one student and wounded four others, including two of Fryberg's cousins, and gatherings were planned Sunday afternoon in the high school gym and at a tribal center.

In the nearby community of Oso, where a mudslide this spring killed dozens, people planned to gather to write condolence letters and cards.

Of the wounded students, only 14-year-old Nate Hatch showed improvement, though he remained in serious condition in intensive care at Harborview Medical Center in Seattle. Fifteen-year-old Andrew Fryberg also remained in critical condition in intensive care. Both are cousins of Jaylen Fryberg.

Meanwhile, 14-year-olds Shaylee Chuckulnaskit and Gia Soriano remained in critical condition in intensive care at Providence Regional Medical Center in Everett.

The girl killed in the shooting hasn't been officially identified.

Fryberg died in the attack, after a first-year teacher intervened. It's unclear if he intentionally killed himself or if the gun went off in a struggle with teacher Megan Silberberger.

The Snohomish County medical examiner's office said it was unlikely to have autopsy results before today.

Remle said he knew Fryberg and the other students well.

"My office has been a comfort space for Native students," he said. "Many will come by and have lunch there, including the kids involved in the shooting."

They all were "really happy, smiling kids," Remle said. "They were a polite group. A lot of the kids from the freshman class were close-knit. Loving.

"These were not kids who were isolated," he said. "They had some amazing families, and have amazing families."

These factors make the shooting that much more difficult to deal with, "Maybe it would be easier if we knew the answer," Remle said. "But we may never know."