CHICAGO (AP) — A judge Wednesday sentenced a Chicago man to 11 years in prison for sexually assaulting a 7-year-old female relative in an act witnessed in an online forum used for remote teaching.

Catrell Walls, 21, pleaded guilty to a felony sexual assault charge for the Oct. 15, 2020, attack. As part of a plea agreement, prosecutors dropped two other felony counts and an unrelated weapons case, the Chicago Tribune reported.

The assault took place at a home from which the girl was participating in class remotely during the COVID-19 pandemic, prosecutors said. During a break, the teacher asked students to mute themselves and turn off their cameras. The girl muted herself but she did not turn off the camera, and the teacher witnessed the assault, prosecutors said.

The teacher contacted the school’s principal, who called the girl’s family, Chicago police and the Illinois Department of Children and Family Services, prosecutors said.

When the girl’s father, the principal and the school’s chief executive officer went to the South Side home to ask her what happened, she told the principal about the assault and said it had happened before, prosecutors said. Walls was then arrested. The girl was treated at a hospital.

Walls has been diagnosed with attention deficit hyperactivity disorder, which impairs his ability to control his impulses, an attorney for him said at the time of his arrest.

Authorities did not say how Walls and the girl were related.