PORTLAND – A Norway man who challenged the constitutionality of a child pornography law before being convicted of having illegal images on his computer is going to prison for 40 months.

David Hilton was convicted by a federal judge last June after his indictment was originally thrown out on constitutional grounds. The 1st Circuit Court of Appeals later reinstated the indictment.

Hilton, 49, was accused of possession of child pornography transported to his computer over the Internet.

Hilton characterized himself as an anti-pornography crusader but federal officials questioned his motives. He was charged after he continued to collect material despite warnings that it was illegal to do so.

A federal agent testified during his January trial in U.S. District Court that investigators found 2,000 to 3,000 pornographic images on Hilton’s Zip drives, backup tapes and computer itself.

The 40-month sentence was imposed Friday in U.S. District Court. Hilton also must serve three years of probation after leaving prison.

Hilton’s lawyer originally challenged the statute under which the charges were brought: the Child Pornography Protection Act of 1996

The law, which targets new computer technology, makes it illegal to possess pornographic images of children, regardless of whether the images show a real child or an altered image.

It was designed by Congress to target computer technology that can be used to alter an innocent picture of a child into a picture of a child engaged in a sexually explicit act.

U.S. District Judge Carter originally ruled that the language of the law was unconstitutionally vague. But he was overruled by the 1st U.S. Circuit Court of Appeals, which upheld the law’s constitutionality.

Federal prosecutors proceeded with the charge after the U.S. Supreme Court refused to intervene in the case.