The Nebraska Department of Correctional Services say 68-year old Frank Hardy died earlier this week at the Tecumseh State Correctional Institution.
His sentence started May 4th, 2011.
Hardy was serving a 75 to 95 year sentence on charges out of of Gage County that included first degree sexual assault of a child, third degree sexual assault of a child and visual depiction of sexually explicit conduct.
The official cause of death has not yet been determined, though Corrections says Hardy was being treated for a long-term medical condition.
Nebraska law calls for a Grand Jury investigation whenever someone dies in custody.
(Picture from Nebraska Department of Correctional Services)