One of the teenagers wounded in a Washington state high school shooting died on Sunday, raising the number of fatalities to three.

Officials at Providence Regional Medical Centre have confirmed the death of 14-year-old Gia Soriano. Another girl was killed during the shooting on Friday at Marysville-Pilchuck High School north of Seattle. The shooter, Jaylen Fryberg, died of a self-inflicted wound.

Three other students remain in hospital, two in critical condition and one in serious condition.

• Candlelight vigils as teens fight for their lives

At a news conference, Dr Joanne Roberts read a statement from Gia’s family.

“We are devastated by this senseless tragedy. Gia is our beautiful daughter, and words cannot express how much we will miss her,” the statement said.

Roberts said Gia’s family was donating her organs for transplant.

Earlier on Sunday, parents and students gathered in a gymnasium at the school for a community meeting, with speakers urging support and prayers and tribal members playing drums and singing songs. Fryberg was from a prominent Tulalip Indian tribes family.

Young people hugged each other and cried and speakers urged people to come together during the gathering.

“We just have to reach for that human spirit right now,” said Deborah Parker, a member of the Tulalip Indian tribes.

“Our legs are still wobbly,” said Tony Hatch, a cousin of one of the injured students. “We’re really damaged right now.”

Of the wounded students, only 14-year-old Nate Hatch showed improvement, though he remained in serious condition in intensive care at Harborview Medical Centre in Seattle.

Fifteen-year-old Andrew Fryberg also remained in critical condition in intensive care. Both are cousins of Jaylen Fryberg.

Meanwhile, 14-year-old Shaylee Chuckulnaskit remained in critical condition in intensive care at Providence Regional Medical Centre.

The girl killed in the shooting Friday 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 a teacher.

The makeshift memorial on a chain link fence by the school, which will be closed this week, kept growing Sunday. Balloons honouring the victims and the shooter adorn the fence along with flowers, stuffed toys and signs.

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 motivated Fryberg.

“We can’t answer that question,” said Matt Remle, who has an office at Marysville-Pilchuck High School, which is 30 miles north of Seattle. “But we try to make sense of the senselessness.”