MANSFIELD, Texas (CBSDFW.COM) – Tarleton State University professor Dr. Alex del Carmen said the law enforcement response to Tuesday’s active shooter situation at Timberview High School in Mansfield was ‘textbook.’

“You have a coordinated response, from police agencies and they know what they are doing. They are going through the scene, left, right, up and down to make sure there are no details left uncovered. They’re interviewing witnesses and pursuing the suspect at this point (I assume, very aggressively) throughout the area. And possibly the state,” said Del Carmen, associate dean and professor in the College of Liberal Arts’ School of Criminology, Criminal Justice and Strategic Studies.

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He also had some words of advice for worried parents.

“I have worked with some of the agencies involved today, and I can assure you they’re the best of the best. There was an immediate response from the Secure Team to remove victims and get them to the hospital,” he said.

As for the person of interest, alleged shooter and student, Timothy George Simpkins, Del Carmen said the operation’s success will come down to his apprehension. “Until he’s taken into custody, parents and local residents will remain very nervous.”

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The “all clear” was given at Timberview High School in Arlington several hours after the 18-year-old took off from campus in his silver charger.

Arlington Assistant Police Chief Kevin Kolbye confirmed there were four victims from the situation. Three people were transported to a local hospital. One injured person refused treatment at the scene.

Officials with the Arlington Police Department confirmed that the ATF Dallas Field Division, Mansfield PD, Grand Prairie PD, and Mansfield ISD police are all working the scene and are doing a ‘methodical search’ of the campus.

Mansfield ISD has set up a reunification location where adults can pick up students. Parents are being told to go to the Center for Performing Arts, located at 1110 West Debbie Lane in Mansfield. Police say students will eventually be bused to the location after the school is completely secured and officers will be on the scene. The current student population is around 2,000.

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