A man who held two children at gunpoint during a robbery in their apartment was sentenced to 15 years in prison, the Cobb County district attorney said Friday.

Herbert Maurice Belle, 35, of Stone Mountain pleaded guilty to armed robbery and cruelty to children in the April 2013 incident inside an apartment off Windy Hill Road, according to the DA’s office.

Belle told the court he and a man he knew only as “Tony” believed they were going to buy drugs when they knocked on an apartment door. Instead, a 17-year-old girl answered the door and told the men her father was not home, prosecutors said.

The two men then each pulled out handguns and forced their way into the apartment, where they threatened the teen and her 8-year-old cousin, holding them both at gunpoint while ransacking the apartment. The two men stole various items, including cash and cell phones, according to investigators.

“Regardless of what Mr. Belle thought he was going to that apartment for that day, once there he became an equal participant in terrorizing two innocent young girls,” assistant DA Theresa Schiefer told the court.

Judge Stephen Schuster sentenced Belle to 20 years, including 15 years to serve in prison and the remainder on probation.