The Spokesman-Review reports that first responders were at Freeman High School in Rockford Wednesday morning. KREM reports the suspected shooter is in custody.
"The threat from the shooter has been eliminated," Spokane Fire Chief Brian Schaeffer told the station.
Schaeffer told the station one student died inside the school and several were injured.
CBS News confirms a local hospital is treating three "school age" patients. Providence Sacred Heart Medical Center and Children's Hospital received three pediatric patients, spokeswoman Nicole Stewart said. They were in stable condition, and family members were with them, she said.
Fire officials would not confirm the age of the deceased victim.
Ambulances and a Lifeflight helicopter were sent to the school. Freeman School District schools were also on lockdown. The Spokane Sheriff's office said on Twitter law enforcement was sweeping the school floor by floor.
Spokane Public Schools said on Twitter Wednesday morning that all schools in the district "are in full lockdown as a precautionary measure," and later tweeted the lockdown had been lifted.
Annie Baxter, whose two daughters attend Freeman Middle School across the street from the high school, told The Spokesman-Review that children were running into buildings when she pulled up to the school area about 10:15 a.m.
She says classes were about to begin because it's a "late start" day.
Worried parents rushed to the school in the town of about 500 people near the Idaho border, about 25 miles southeast of Spokane. The two-lane road into town was clogged as people sped to the school.
Cheryl Moser said her son, a freshman at Freeman High School, called her from a classroom after hearing shots fired.
"He called me and said, 'Mom there are gunshots.' He sounded so scared. I've never heard him like that," Moser told the newspaper. "You never think about something happening like this at a small school."
Stephanie Lutje told The Associated Press that she was relieved to hear her son was safe after his high school near Freeman was put on lockdown. She commended the school district for its communication with parents.
"It's been amazing, within probably 15-20 minutes of hearing about it, I'd already received a phone call, I'd already received a text message saying that their school is OK," she said.
She still worried for others she knew, including a co-worker who had yet to hear from her son, a sophomore at Freeman.
"My stomach's in knots right now," she said.
Gov. Jay Inslee said in a statement that "all Washingtonians are thinking of the victims and their families, and are grateful for the service of school staff and first responders working to keep our students safe."