A former substitute teacher in Charles County, Maryland,has been convicted of sexual abuse of a minor, a middle school student.

Thirty-one-year-old Keith Allan Kirkstan of Waldorf, Maryland, was convicted on Tuesday after a five-day trial.

He was teaching at John Hanson Middle School when prosecutors say the abuse involving the 12-year-old began. They say it started in October 2017.

Kirkstan and the victim talked via Snapchat, FaceTime and text. Prosecutors say he sent the victim pictures of his genitalia, and asked her to send photos of her private areas to him, which she did. One day, Kirkstan held her back from class to talk, writing her a pass to be late to her next class.

In January of 2018, one of the victim’s classmates learned what happened, and told a school resource officer.

Cellphone data showed the inappropriate communication, and Kirkstan admitted to communicating with the victim and deleting messages.

During closing arguments, Assistant State’s Attorney Sarah Freeman said that Kirkstan “took advantage of [the victim] for his own benefit. He knows this is wrong, yet he [continued] because his needs were more important [to him] than doing what’s right.”