UPPER MARLBORO, Md. — Authorities in Maryland say they have identified “dozens” of potential victims in a child pornography case involving a former substitute teacher and basketball coach.

The Prince George’s County State’s Attorney’s office issued a statement Friday urging parents to call authorities if they believe their child had contact with Christopher Speights, who taught and coached at an elementary school and who also coached a traveling basketball team. Investigators believe there could be more victims who haven’t been identified.

Speights was arrested in April, and has been indicted on state and federal child pornography charges. The Washington Post reports he entered a not guilty plea to the federal charges in August.

His state case is set for trial in November.

He’s being held without bond and also has a federal detainer filed against him.