Daniel Dak died Sunday at the Reception and Treatment Center in Lincoln. He was 33 years old.
Dak was serving an 18- to 36-year sentence out of Lancaster County for robbery and use of a firearm to commit a felony. He began his sentence in October 2011.
The Nebraska Department of Correctional Services (NDCS) did not provide any additional information about his death.
As is the case whenever an inmate dies in the custody of NDCS, a grand jury will conduct an investigation.