An 18-year-old student opened fire during a fight at his Dallas-area high school on Wednesday, injuring four people and then fleeing before being taken into custody hours later, authorities said.

Timothy George Simpkins was taken into custody without incident and charged with multiple counts of aggravated assault with a gun, the Arlington Police Department tweeted.

The shooting at Timberview High School, which is in Arlington but belongs to the school district in neighbouring Mansfield, stemmed from a fight that broke out in a classroom, Arlington Assistant Police Chief Kevin Kolbye said at a news conference before Simpkins’ arrest.

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Two people were shot and two others had unspecified injuries, he said. At least three of the injured are students, and three of the four injured were taken to hospitals, he said.

“This is not a random act of violence,” he said. “This is not somebody attacking our school.”

Timberview serves about 1,900 students in the ninth through 12th grades. The sprawling complex opened in 2004.

After news of the shooting spread, parents gathered at the Mansfield Independent School District Center for the Performing Arts about 5 miles (8 kilometers) from the high school to be reunified with their kids, who were bused over. Among them was Justin Rockhold, whose ninth-grade son had texted him to let him know he was OK.

Rockhold said he has served in the military and he drew on that experience to instruct his son, telling him to keep his head down and be still to stay safe. When asked whether he had thought a could happen at the school, he said his military training is also a reminder of life’s dangerous realities.

“Obviously in America — in the world we live in today — it’s always something. … It’s in the back of your mind,” Rockhold said, adding that he was praying for the injured. “I’m just blessed today that my kid’s safe.”

The shooting happened just days after a shooting at a Houston charter school that injured an administrator. Texas’ deadliest school shooting occurred in May of 2018 when a then-17-year-old armed with a shotgun and a pistol opened fire at Santa Fe High School near Houston, killing 10 people, most of whom were students.