A Cheyenne man previously convicted of sexually assaulting a child is headed back to prison after authorities found a massive collection of child porn on his home computers.

Person's child porn collection was the largest ever seized in the U.S.

63-year-old Richard Person was sentenced in U.S. District Court Tuesday to 19 years and seven months in prison for a single count of possession of child pornography.

The National Center for Missing and Exploited Children and Internet Crimes Against Children (ICAC) say Person's child porn collection was the largest ever seized in the U.S.

Person had previously served eight years in prison for a 2001 conviction of sexually assaulting a child.