The parents of a 15-year-old Oregon boy who killed a classmate when he opened fire in his high school locker room apologized Friday, saying they were "horrified and distraught" by the shooting.

The letter from Michael Padgett and his ex-wife, Kristina, was delivered to KPTV, the Fox affiliate in Portland, three days after Jared Padgett fatally shot 14-year-old Emilio Hoffman at Reynolds High School in suburban Troutdale. Physical education teacher Todd Rispler was injured when another bullet grazed him. Padgett killed himself in a bathroom after he was confronted by officers.

"We are at a loss as to how and why this tragedy unfolded," the letter read, in part. "Our family does not condone and has never promoted violence or hatred toward anyone. The values that we have taught our children are love in Jesus Christ, compassion, forgiveness, and patience. These were all natural attributes we observed within Jared daily. Knowing that these are the values that we have taught our children, we are horrified and distraught by the actions perpetrated by our son."

Investigators have yet to reveal a possible motive, and the statement shed no light on what may have led the devout Mormon and aspiring serviceman to become a school shooter.

A public service of Hoffman's memory has been set for June 22. Hoffman's older brother wore Emilio's no. 29 Reynolds High School soccer jersey when he walked across the stage at Thursday's graduation ceremony. 

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The Associated Press contributed to this report.