Jeff Anderson said he filed a civil suit in U.S. District Court this morning against former St. Paul schoolteacher and foster parent Gregg Alan Larsen and 100 as-yet-unnamed child pornography downloaders.

Larsen, 49, of Minneapolis was indicted May 19 and charged with production, distribution and possession of child porn.

"If you choose to download images of child pornography, we will find you, we will track you and we will expose you," Anderson said.

He said his office is working with police, specifically the Minnesota Internet Crimes Against Children task force, to trail the digital footprints of downloaded material ? whether it is viewed on a computer or a phone. He promised to send out press releases as the names of offenders who view and trade images are revealed and add their names to the lawsuit.

Larsen's criminal attorney, Joseph Tamburino, did not immediately return a call seeking comment.

The plaintiffs in the lawsuit are a boy, who was about 9 at the time of the 2006 abuse, and his parents. The child's mother provided daycare to Larsen's children and foster children, and the boy sometimes went swimming with Larsen and his children and spent the night at their home.

While at the home, "(Larsen) engaged the plaintiff