WHITE PLAINS, N.Y. - An instructor who taught private music lessons to children and adults pleaded guilty in federal court Monday to one count of receiving child pornography and one county of possessing child pornography, following an investigation by U.S. Immigration and Customs Enforcement's (ICE) Homeland Security Investigations (HSI). Stephen W. Siktberg, 32, was arrested by HSI agents on Oct. 29, 2010, at his home in Beacon, N.Y. He entered his guilty pleas before U.S. Magistrate Judge Lisa Margaret Smith in White Plains.