EVERETT – The five students targeted in Friday’s shooting at Marysville-Pilchuck High School were invited to the cafeteria by the freshman who shot them, authorities revealed Monday.

The 15-year-old shooter, Jaylen Fryberg, texted the other students Friday morning asking them to meet him for lunch, Snohomish County Sheriff Ty Trenary said during a news conference in Everett.

Once the five were seated at a round table in the school’s main cafeteria, Fryberg opened fire with a handgun, fatally shooting two and wounding three others before taking his own life.

The .40-caliber Beretta handgun used by Fryberg was legally purchased, registered and owned by one of the teen’s relatives, Trenary said.

Trenary said investigators with the Snohomish Multi-Agency Response Team are working to determine how Fryberg obtained the weapon.

He declined to say whether the teen left a suicide message or note, saying investigators still were wading through a “tremendous amount of telephone and text messages.”

The investigation could take months to wrap up and, even then, he said, Fryberg’s motive may never be completely understood.

Described as a “golden boy,” Fryberg was a well-liked member of the football team who a week before the shooting had been crowned freshman homecoming prince. Some believed he could have become a leader of the Tulalip Tribes.

Some students have said he had been experiencing problems with a girl; others indicated he may have had some type of dispute with fellow students. But the victims who were gunned down were relatives and friends of Fryberg’s.

“The question everybody wants is why, and quite candidly I don’t know the why is something we can provide,” Trenary said.

Investigations into school shootings across the country have taught that “the why is elusive,” he said.

Earlier Monday, the Snohomish County Medical Examiner’s Office formally classified Fryberg’s death as a suicide due to a gunshot wound to the head.

Officials also released the name of victim Zoe Galasso, 14, who died in the cafeteria Friday of “a handgun wound of the head.”

Sunday night, Gia Soriano, 14, died at Providence Regional Medical Center in Everett. She had been hospitalized in critical condition since the shooting.

Three other teens remain hospitalized. Two are in critical condition, but one appears to be recovering.

Shaylee Chuckulnaskit, 14, was in critical condition at Providence Regional Medical Center.

Andrew Fryberg, 15, was in critical condition in the intensive-care unit at Seattle’s Harborview Medical Center, according to hospital spokeswoman Susan Gregg.

The third injured teen, Nate Hatch, 14, was also in Harborview’s intensive-care unit, but his condition has improved to satisfactory, according to Gregg. He is awake and breathing on his own, Gregg said.

Hatch posted a message of forgiveness on Twitter.

“I love you and I forgive you jaylen rest in peace,” he wrote. A friend confirmed the feed’s authenticity to the Associated Press.

Trenary, the Snohomish County sheriff, also addressed reports that a first-year teacher confronted the shooter, saying that the teacher did not have physical contact with Fryberg.

Randy Davis, the president of the Marysville Education Association, said the teacher is shaken and does not want to be interviewed.

But he clarified her involvement in a phone interview Monday.

Davis said the teacher was in an office next door to the cafeteria when she heard gunfire and ran into the cafeteria.

“At that point she saw the students on the ground and saw the shooter,” Davis said. “From what I understand, she ran toward the shooter and confronted him verbally, saying, ‘Stop, stop stop!’ and then it was a suicide and stayed there until the security officer arrived.”

The Marysville School District will host a meeting today to provide information to parents on how to offer support for their children after the shooting. The meeting is scheduled for 7 p.m. at the Marysville-Pilchuck gym. The high school, attended by about 2,000 students, is closed all week.

Schools in the rest of the Marysville School District observed a moment of silence at 10:39 a.m. Monday, to mark the moment of the shooting, before continuing with classes.

All day Monday, students, parents and others came to the high school to tuck flowers and notes into a chain-link fence around the school and to tie red and gold balloons to it.

Rachael Newton, who came with a group of seniors, said the school is so close-knit, it feels like the victims and shooter were all family.

“We all cared about them,” Newton said. “They were just freshmen. So not only were they family, they were some of our youngest family members.”

“There are people who are angry at Jaylen,” said Newton’s friend Ryan Edwards, “but we’re here to show support and love for everyone.”