A Barnesville man was sentenced to 20 years in federal prison after entering a guilty plea to producing child pornography over an 11-year period.

Timothy Russell Steward Jr., 39, will also be placed on supervised release for the rest of his life, ordered U.S. District Judge Richard P. Conaboy.

Additional conditions imposed by Judge Conaboy in his ruling, made in U.S. District Court, Scranton, are that Steward shall have no contact with any person under the age of 18, except in the presence of an adult who is aware of the nature of his background, and the defendant shall not reside or loiter within 1,000 feet of places where children under the age of 18 congregate, which includes playgrounds, schools, parks, day care centers, arcades, and youth sporting events.

Steward, who was indicted by a federal grand jury on the charges, pleaded guilty to producing child pornography between January 2000 and December 2011.

In the three-count indictment, two of the three charges were dismissed in exchange for his guilty plea.

He pleaded guilty to sexual exploitation of children. Charges dismissed included "certain activities related to material constituting or containing child pornography."

The guilty plea states Steward "did use, employ, persuade, induce and entice a person under the age of 18 to engage in sexually explicit conduct for the purpose of producing a visual depiction of such conduct" and that the materials "have been mailed, shipped, and transported in interstate and foreign commerce by any means."

Steward was arrested Dec. 23, 2011.

A federal grand jury indicted him on Feb. 2.

He initially pleaded not guilty to the charges, but changed his plea to guilty on April 16, 2012.

The indictment resulted from an investigation by the Pennsylvania State Police Computer Crimes Unit and the U.S. Immigration and Customs Enforcement's Homeland Security Investigations, prosecutors said.

The National Center for Missing and Exploited Children assisted in the investigation, according to prosecutors.

Authorities said the investigation revealed that Steward produced numerous pornographic pictures of a young boy and saved them on various forms of media. A forensic examination of Steward's computer and other media revealed additional images of alleged child pornography that he received and possessed.