MARYSVILLE, Wash. (KABC) -- A newly hired high school teacher confronted a gunman during a deadly shooting at a Washington state school, a union official said.
Marysville Education Association president Randy Davis said Saturday that first-year social studies teacher Megan Silberberger intervened in the shooting at Marysville-Pilchuck High School, north of Seattle.
Meantime, Snohomish County Sheriff's spokeswoman Shari Ireton said in a statement also on Saturday that the on-scene investigation at the school was finished.
PHOTOS: Marysville High School shooting scene
Sources told ABC News that the shooter was identified as Jaylen Fryberg, a freshman at Marysville-Pilchuck High School. Students and parents say Fryberg played on the school football team and was recently crowned as a homecoming prince. Authorities confirmed that the gunman died of a self-inflicted gunshot wound.
A .40-caliber handgun was recovered from the school. Ireton said it is believed that was the weapon used in the Friday morning shooting that left one victim dead and four others injured.
Marysville police have said the gun used in the shooting was legally acquired, though they have not said by whom.
Marysville Police Administrative Commander Robb Lamoureux said the fatal shooting victim was a female, but did not say whether it was a student or a staff member.
Two of the injured victims, 14-year-old Nate Hatch and 15-year-old Andrew Fryberg, are relatives of the shooter, according to Hatch's grandfather and a source within the Tulalip Tribes. Marysville-Pilchuck High School has a number of students from the Tulalip Indian tribes.
"My grandson and the shooter were best friends," said the boy's grandfather, Donald Hatch. "They grew up together and did everything together."
Andrew Fryberg underwent surgery for a head wound, said Dr. Joanne Roberts, chief medical officer at Providence Regional Medical Center. He and Hatch, who had less serious injuries, were transferred to another hospital.
Andrew Fryberg is listed in critical condition, while Hatch is in serious condition.
The other victims, Shaylee Chucklenaskit and Gia Soriano, both 14, remain in critical condition, said Roberts. Their head injuries were so severe they were not immediately identifiable, and officials met with relatives to ask about birthmarks and descriptions of their children's clothing to help make a match. Roberts said the girls have constant bedside medical attention, and closely monitoring them in the next two to three days will be crucial in their recoveries.
Authorities said two other students were treated for minor injuries at the school.
It all started Friday morning when a 911 caller reported the shooting at 10:39 a.m. Authorities say security officers arrived at the cafeteria minutes later, then confirmed that the shooter was down.
Marysville-Pilchuck High School will be closed all of next week, schools Superintendent Becky Berg said.
At this point, police say the motive remains a mystery. Students described Jaylen Fryberg as a nice, normal kid and say nothing appeared out the ordinary at school Thursday.
Approximately 2,700 students attend the school 30 miles north of Seattle.
ABC News and the Associated Press contributed to this report.