MINNEAPOLIS (AP) — A federal judge says an FBI pornography search was unconstitutional but that the evidence found can still be used against a northeast Minnesota man.

U.S. District Judge John Tunheim found that FBI agents exceeded the scope of a Virginia search warrant when examining hundreds of computers that were reportedly used to access a secretive child pornography site that once had 150,000 users, the Star Tribune reported.

The FBI arrested the website’s operator and seized its server in 2015. The FBI kept a version of the website running and used software to gather IP addresses and other information about the site’s users. That information has been used in several criminal cases across the U.S.

U.S. Magistrate Judge Franklin Noel had recommended suppressing evidence against Terry Lee Carlson that was gathered during two searches of his Coleraine home in 2015 and 2016.