KNOXVILLE, Tenn. (AP) — The mother of a teenage boy who was killed by police in his Tennessee high school has filed a federal lawsuit over the shooting.

Chanada Robinson filed suit Monday against the city of Knoxville, the Knoxville Police Department and the Knox County Board of Education in the death of her 17-year-old son, Anthony Thompson Jr., last year at Austin-East High School, news outlets reported.

The suit alleges officers didn’t follow proper training and procedures, didn’t provide appropriate medical care and weren’t properly trained on de-escalation tactics.

Robinson is seeking damages that include the cost of burial for her son and additional training for the Knoxville Police Department.

“We need to get to the heart of what happened to Anthony. We need to see some policy changes so that this never happens again, (so that) there’s never another mother sitting in my position,” Robinson said.

Knox County District Attorney General Charme Allen determined the shooting was justifiable under Tennessee’s self-defense law last year.

Video footage of the April 12, 2021, shooting shows four officers responded to the school after a domestic abuse call from the mother of Thompson’s former girlfriend. The officers went into a bathroom where they believed Thompson was, but Allen’s office said the officers did not know the teen was carrying a handgun.

The video shows the officers locating and then attempting to handcuff Thompson. One officer grabbed Thompson’s right arm, but Thompson’s left arm was in his sweatshirt pocket, where the video shows he was holding a handgun. The barrel of the weapon could be seen peaking through the pocket. Thompson’s weapon went off, hitting a trash can but not any of the officers.

The shot confused the officers into thinking their lives were in danger and one of them was potentially injured, Allen said — pointing to the various statements they later gave investigators.

Officer Jonathon Clabough can be seen removing his weapon and shooting Thompson in the shoulder. Allen said the officers did not know Thompson had been shot until two minutes after handcuffing him and turning over his body. That’s when they saw the large amounts of blood and called the school nurse for medical assistance.

Knoxville police, the city and Knox County Schools declined to comment, citing the pending litigation.

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