May 6 (UPI) -- Two students and one adult sustained injuries Thursday after a sixth-grade student opened fire at an Idaho middle school, police said.
Jefferson County Sheriff Steve Anderson said officers arrested the suspected gunman, who pulled a gun from her backpack at Rigby Middle School and shot two people. She went outside the school and shot a third person, he added.
Anderson said a teacher disarmed the student and detained her until police arrived at the scene.
"This is the worst nightmare a school district could ever face," Superintendent Chad Martin said during a news conference. "We prepare for it, but we're never truly ready for it."
Officials said the adult was treated and released from Eastern Idaho Regional Medical Center and the two students were receiving treatment for non-life-threatening injuries. One of the injured students may require surgery.
Michael Lemon, the trauma medical director at the hospital, said one of the students received a gunshot wound to an extremity, and the second student was possibly shot twice.
"The fact that the injuries are as insignificant as they are right now ... they could be so much worse. We feel absolutely blessed," Lemon said.
Students from the middle school were transported to a nearby high school for their parents and guardians to pick them up. Rigby Middle School has more than 1,400 students enrolled in sixth, seventh and eighth grades.
Authorities were investigating a motive for the shooting.