LINCOLN, Neb. -- A 64-year-old Nebraska inmate died in custody Monday morning.

Russell Harms, who had been serving a life sentence, died in the Reception and Treatment Center in Lincoln. He began serving his sentence on October 11, 2000, after being convicted of first-degree murder and use of a deadly weapon to commit a felony.

Harms was convicted in Nemaha County in connection to the shooting death of 84-year-old Tennyson Kelsay in an Auburn parking lot in December of 1999. Harms shot Kelsay 15 times, firing from the window of his pickup.

Kelsay was the grandfather of Chad and Chris Kelsay, both of whom were standout defenders for the Nebraska football team. At the time of the shooting, Chad Kelsay was with the Pittsburgh Steelers, while Chris Kelsay was still on the Huskers' roster.

The cause of Harms' death has not yet been determined. As is the case whenever an inmate dies in the custody of the Nebraska Department of Correctional Services, a grand jury will conduct an investigation.