U.S. Marshals arrested a Thornton man in Denver on a warrant related to sex assault on a child in Pueblo County, according to a Thursday news release from the Pueblo Sheriff's Office.
Austin Halderman is charged with sexual assault on a child, sexual exploitation of a child and aggravated incest.
The release stated that the investigation began in August after a school resource officer in a District 70 elementary school received a tip of a possible assault.
Detectives believe that Halderman had "inappropriate relations" with a child for at least three years, and they processed evidence that contained child sexual abuse material, according to the release.