The school district fired her, local police charged her with aggravated assault, and the governor of Texas promised a state investigation after a substitute teacher's violent altercation with a student was caught on video and went viral on social media.

Tiffani Shadell Lankford, 32, was teaching a foreign language class Friday at Lehman High School in Kyle when, in the video, she appears to walk up to the desk of a student and punches her repeatedly, then pulls her from her desk, throws her to the floor and stomps on her as stunned students climb out of their desks.

"Conduct like this won't be tolerated in Texas classrooms," Gov. Greg Abbott said in a statement. "The substitute teacher who committed this heinous act has been arrested and will face serious legal consequences."

He said the district will be investigated by the Texas Education Agency. Lehman is a four-year high school with about 2,500 students in the Hays Consolidated Independent School District, about 20 miles south of Austin.

The district issued a statement expressing support for the student and her family after the "horrible incident." The student victim was a 16-year-old sophomore, the district said in a statement post on Facebook.

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"As a Hays CISD family, when one of our schools and students is hurting, we all hurt," the district said in the Facebook post. "It was a traumatic event for the student, her classmates, and the teachers and staff at Lehman High School."

Classmates alerted other adults on campus that the assault was underway, and Lankford was immediately removed from the classroom and questioned by school resource officers, school officials said. The student's father took her to a hospital; it was not immediately clear what if any injuries she suffered.

“Under no circumstance is that behavior tolerated at Lehman High School,” Lehman Principal Karen Zuniga said. “We take the safety and security of our students seriously. We took swift action when this incident occurred and will do everything necessary to protect our students.”

The district said it, too, was reporting the incident to the Texas Education Agency and would cooperate with law enforcement investigators.

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The substitute teacher had worked the district since the beginning of the school year, when she underwent orientation training. Her first substitute job in a classroom for the district was Sept. 13, and she had worked in a classroom in the district a total of 18 times.

Lankford, like all substitute teachers, was required to pass a background check to work in the classroom.

“We are appalled at the actions of this former employee,” said Tim Savoy, chief communication officer for Hays CISD. “There is absolutely no excuse or circumstance that can justify what you see unfold on the video. It is unconscionable what this adult did to one of our students.”