DALLAS, Texas – Surveillance video captures the moment 17-year-old Tracy Haynes entered a classroom, then returned to the hallway where he opened fire on a group of students before fleeing the scene.

Four students were injured, including three with gunshot wounds, after a shooting occurred Tuesday afternoon at Wilmer-Hutchins High School in southern Dallas.

The incident marks the second shooting on the same campus in just over a year.

Dallas Independent School District (DISD) officials said the shooting was reported at approximately 1:00 p.m., prompting an immediate and large-scale emergency response.

Students were seen evacuating the main school building as police worked to secure the scene and search for the suspect.

According to Dallas Fire-Rescue, four students — ranging in age from 15 to 18 years old — were transported to area hospitals.

Three of the students sustained gunshot wounds, while a fourth suffered a musculoskeletal injury to the lower body.

Their injuries were described as ranging from serious to non-life-threatening.

“This is the unthinkable — and sadly, it’s becoming all too familiar,” said DISD Superintendent Dr. Stephanie Elizalde during a news conference Tuesday afternoon.

“No student, teacher, or parent should have to fear violence in a place meant for learning.”

The suspected gunman was identified shortly after the incident, and by 9:32 p.m., 17-year-old Tracy Haynes was taken into custody and booked into the Dallas County Jail.

He is charged with aggravated assault – mass shooting, and his bail was set at $600,000.

It is unclear at this time whether Haynes has obtained legal representation.

Officials confirmed the firearm used in the shooting did not enter the building during the school’s primary intake period, when students are screened through metal detectors and subject to clear backpack policies.

However, authorities declined to say how the weapon entered the premises, or what events led to the shooting inside the school.

“We can confirm that this was not a failure of our staff, of our protocols, or the equipment in place,” said Assistant Chief Christina Smith with the DISD Police Department. “But this is still a very fluid and ongoing investigation.”

More than 20 law enforcement units responded to the shooting, including Dallas ISD Police, the Dallas Police Department, and federal partners from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Texas Governor Greg Abbott was briefed on the situation and offered state resources to assist in the aftermath.

In response to the incident, district leaders announced that classes would be canceled for the remainder of the week, and counseling services would be made available to all students and staff affected by the shooting.

A reunification site was quickly established at Eagles Stadium, where parents were asked to bring photo identification to retrieve their children.

This incident comes almost exactly one year after a student was shot inside a classroom at Wilmer-Hutchins High School, further heightening concerns over school safety in the district.

Authorities urge anyone with additional information related to the incident to come forward as the investigation continues.