(NewsNation Now) — Four people were injured in a shooting at a Texas high school Wednesday and the suspect was arrested after a brief manhunt.

The shooting at Timberview High School, located outside the Dallas -Fort Worth area, stemmed from a fight that broke out in a classroom, Arlington Assistant Police Chief Kevin Kolbye said at news conference.

As of Wednesday evening, a 15-year-old boy was in critical condition after being shot, a 25-year-old man was in good condition after being shot and a third person, identified as a teenage girl, was treated for minor abrasions and released from the hospital, police said. A fourth person was hurt but did not require treatment at a hospital.

Police reported earlier three of the victims were Timberview students and another may have been a teacher. One of the victims was pregnant, police said.

“This is not a random act of violence,” Arlington Assistant Police Chief Kevin Kolbye said at the news conference. “This is not somebody attacking our school.”

Police released a mugshot of the suspect, 18-year-old Timothy George Simpkins, Wednesday morning. After a brief manhunt, Arlington police arrested Simpkins Wednesday afternoon.

He was booked on three counts of aggravated assault with a deadly weapon and was being held on $75,000 bail. Police said they have recovered a handgun but are working to confirm it was the weapon used.

A spokeswoman for Simpkins’ family said he had been bullied and robbed twice at school.

“The decision he made, taking the gun, we’re not justifying that,” said family spokeswoman Carol Harrison Lafayette, who spoke to reporters outside the Simpkins’ home while standing with other relatives. “That was not right. But he was trying to protect himself.”

Student Hanyla Milligan said she first got word of the shooting when she heard a commotion.

“Someone outside of my classroom said, ‘He just shot him,” the 16-year-old Milligan said, and then she heard people running. “People were scared. They was crying. They was shaking.

After news of the shooting spread, hundreds of parents gathered at the Mansfield Independent School District Center for the Performing Arts about 5 miles from the high school to be reunified with their kids, who were bused over.  But Ontario Hewitt, who has twins in ninth grade, waited outside one of their classroom windows to make sure he was safe. His other son had already been evacuated.

“I’m a prayer, I believe in Jesus so first thing I started doing was praying and hoping that my kids were safe,” Hewitt said.

The high school is about 20 minutes away from downtown Dallas. Timberview serves about 1,900 students in ninth through 12th grades. The sprawling complex opened in 2004.

Arlington, with a population of about 400,000, is a major suburb of the Dallas-Fort Worth area. The city is home to attractions including the Six Flags Over Texas amusement park and the stadiums where the NFL’s Dallas Cowboys and MLB’s Texas Rangers play. Authorities closed a section of a tollway in Arlington near Timberview as dozens of school buses picked up students to reunite them with their parents. Some waited for hours to collect their children as traffic in the area crawled.

This story is developing. Refresh for developments.

The Associated Press contributed to this report.