A former Federal Way High School volunteer basketball coach was arrested Friday for allegedly raping a 15-year-old female student-athlete, according to police and court documents.

A friend of the victim reported former coach Brianna Strong to a police school resource officer, said Cathy Schrock, a spokeswoman for the Federal Way Police Department. Strong, 23, and the admitted raping the girl when confronted with allegations, according to an affidavit of probable cause outlining the police case.

King County Jail records show that Strong was booked into jail Saturday on investigation of child rape, child molestation, possession of child pornography and viewing child pornography. A judge found probable cause to hold her and set bail at $70,000.

The deadline to file charges is Wednesday.

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The sexual relationship between Strong and the student allegedly began at the end of last year and occurred during car rides home from team events and via text messages, according to Schrock and the affidavit. The document said the two also exchanged nude photographs.

Strong had been a volunteer basketball coach at the school for the junior varsity and C-team women’s basketball programs, according to the South Puget Sound League’s website. KING-TV reported that Strong resigned Friday.

According to the affidavit, Strong is an employee of Delta Air Lines and was arrested at Seattle-Tacoma International Airport.

Federal Way High School interim principal Chad Littrell sent a letter home to families of students who may have come into contact with the coach.

“We depend on our staff, students, parents and community members to be alert to what’s happening with our students, and to notify us when a concern arises. It takes all of us working together to maintain a safe and positive learning environment,” Littrell wrote in the letter, a copy of which was obtained by the Federal Way Mirror.

“This is an opportunity to have those conversations with children about what’s appropriate with members of authority,” Schrock said. “Like it’s not appropriate for coaches and team members to be texting. Also on rides home there needs to be a third party there to make sure that the relationship remains appropriate.”

Erin Heffernan can be reached at eheffernan@seattletimes.com or 206-464-3249.

Seattle Times news researcher Miyoko Wolf contributed to this story.