The Nebraska Department of Correctional Services continues to investigate, and no official cause of death has been determined, but officials say an inmate at the Nebraska State Penitentiary was being treated at a hospital for a medical condition when he died Friday afternoon.
64-year old Mark Nielson died at Bryan Medical Center-West in Lincoln.
He was serving an eight to ten year sentence out of Douglas County for distribution, manufacture and possession of methamphetamine with the intent to deliver.
His sentence began in February of 2016;
Nebraska law dictates that a grand jury be impaneled whenever someone dies in custody or while being taken into custody.