Students said the gunman was staring at his victims as he shot them inside the cafeteria. The shootings set off a chaotic scene as students ran from the cafeteria and building in a frantic dash to safety, while others were told to stay put inside classrooms.
Police say there was only one gunman.
"We are confident there is only one shooter and the shooter is deceased," said Marysville Police Cmdr. Robb Lamoureux in a noon briefing.
The gunman was identified as student Jaylen Fryberg. Students and parents said Fryberg was a member of a prominent family from the nearby Tulalip Indian tribes and a freshman who played on the high school football team. He was introduced at a football game as a prince in the 2014 Homecoming court, according to a video shot by parent Jim McGauhey.
Shaylee Bass, 15, a sophomore at the school, said Fryberg had recently gotten into a fight with another boy over a girl.
"He was very upset about that," said Bass, who was stunned by the shooting.
"He was not a violent person," she said. "His family is known all around town. He was very well known. That's what makes it so bizarre."
'God, let my kids be safe'
Dr. Joanne Roberts at Providence Regional Medical Center said four young victims were transported there after the shootings. Three of them - two girls and a boy - are in very critical condition with head wounds. The fourth student, a boy, is in critical but stable condition, and was airlifted to Harborview Medical Center in Seattle, she said.
The male victim at Providence was later transported to Harborview.
Harborview spokesperson Susan Gregg confirmed that the two male victims, 14-year-old Nate Hatch and 15-year-old Andrew Fryberg, remain in critical condition.
Brian Patrick said his daughter, a freshman, was in the cafeteria 10 feet from the gunman when the shooting occurred. She ran from the cafeteria and immediately called her mother.
Patrick said his daughter told him, 'The guy walked into the cafeteria, pulled out a gun and started shooting. No arguing, no yelling."
His other daughter, a senior at the school, called him 'hysterical' from her classroom, Patrick said.
"I thought, 'God, let my kids be safe," he said.
Student Tanya Christenson said she was in the cafeteria when the shooting happened.
"Four shots went off. I thought it was firecrackers, and then everyone started ducking under the tables, and then everyone started screaming, 'Run, it's a gun!'" she said.
Student: Nothing to indicate Frybeg was upset
Some students described Jaylen Fryberg as a happy, popular student, but social media accounts suggested he was struggling with an unidentified problem.
On Wednesday, a posting on his Twitter account read: "It won't last ... It'll never last." On Monday, another tweet said: "I should have listened. ... You were right ... The whole time you were right."
Marysville-Pilchuck High School has a number of students from the Tulalip Indian tribes.
Ron Iukes, a youth counselor with the tribes, said Jaylen Fryberg was from a well-known tribal family.
"They're real good people, very loving, a big part of the community," he said. "Jaylen was one of our good kids. It's just a shock this happened. I've known this boy since he was a baby."
Nathan Heckendorf, a 17-year-old junior at the high school, said he saw Jaylen Fryberg on Friday morning before the shooting and there was nothing to indicate he was upset.
"He looked happy, everything seemed fine," Heckendorf said.
Oak Harbor football team forfeits to give league championship to Marysville-Pilchuck
State Sen. John McCoy, a tribal member, said the shooting devastated the tribal community.
"We're all related in one shape or form. We live and work and play together," he said.
Hundreds of people prayed and sang at a church vigil Friday night for victims and family members.
The Oak Harbor high school football team, which had been set to play Marysville later that night, lined the front row of Grove Church in their purple jerseys. The game was canceled and Oak Harbor offered to give the win to Marysville.
"It's something we need," Felecia Thompson said about the vigil. "And getting together right away, we can help move through it."
The school district will have counselors available Saturday morning from 9 a.m. to noon at 4220 80th Street NE in Marysville.