At least four people were injured in a shooting at a Dallas-area high school on Wednesday.
Timberview High School in Arlington, Texas, was placed on lockdown following initial reports of an "active shooter situation."
Police believe three of the victims are students and the other an older person who may have been a teacher.
Arlington Assistant Police Chief Kevin Kolbye said two of those injured people were shot. Three of the four were taken to hospital and the other person refused treatment.
"Two will remain in the hospital, which continue to make hopefully a speedy recovery," he said in a second police update, adding that one of the three is out of surgery.
In a news conference, local police identified an 18-year-old suspect was in custody after going on the run "armed and dangerous" for a short period of time.
The suspect will be charged with three counts of aggravated assault with a deadly weapon.
“This is not a random act of violence,” Mr Kolbye said. “This is not somebody attacking our school.”
Authorities said the shooting occurred after a fight broke out at the school.
Live television images showed a heavy police presence around the school, with armed officers searching the sprawling campus and fire trucks on the scene.
Video from WFAA in Dallas showed a single file line of people exiting a school building and long lines of buses stretching outside.
The Timberview school serves about 1,900 students in ninth through 12th grades. The sprawling complex opened in 2004.
On October 1, a former student shot and injured the principal at a nearby school in Houston.
Agencies contributed to this report