On Tuesday (April 20), Derek Chauvin was convicted on all counts in the death of George Floyd. Though the guilty verdict marked the end of his murder trial, ABC reports that he may possibly face charges in connection with an unrelated, but similar incident that took place in 2017.

In a court filing presented during Chauvin’s trial, prosecutor Matthew Frank detailed the former officer’s horrific arrest of a Black teen on Sept. 4, 2017. According to his account, Chauvin and another Minneapolis officer responded to calls of a woman being attacked by her 14-year-old son and young daughter. Shortly after their arrival, they ordered the teen to lie on the ground, but he rejected, prompting Chauvin’s attack.

The former officer allegedly hit the woman’s son with his flashlight before grabbing his throat and applying a neck restraint that resulted in his loss of consciousness.

“Chauvin and [the other officer] placed [the teenager] in the prone position and handcuffed him behind his back while the teenager’s mother pleaded with them not to kill her son and told her son to stop resisting,” Frank wrote, adding the attack caused the teenager’s ear to start bleeding. “About a minute after going to the ground, the child began repeatedly telling the officers that he could not breathe, and his mother told Chauvin to take his knee off her son.”

Chauvin moved his knee from the teen’s neck eight minutes later then placed it on his upper back for another nine minutes. He eventually let up and arrested the then-14-year-old for domestic assault and obstruction with force. The woman’s son was brought to an ambulance and taken to a hospital where he received stitches.

Frank filed the court documents alongside videos of the 2017 incident with hopes that the judge would allow prosecutors to compare his behavior to his treatment of Floyd during Chauvin’s murder trial. The judge denied the motion, but now, the Department of Justice is reportedly weighing whether to charge him for the assault.

Per the Minneapolis Star-Tribune, Minneapolis prosecutors brought witnesses before a federal grand jury to provide testimony related to the incident two months ago. The investigation is still underway.