Brendan Horner, a 25-year-old Nebraska State Penitentiary inmate, was sentenced to 8 to 12 years of extra time for second-degree assault Monday.
Horner is already serving 30 to 45 years for a 2012 road rage shooting.
In March of 2016, a corrections officer smelled marijuana in Horner's cell. While another inmate threw drugs in the toilet, Horner punched the officer several times, according to officials.
The corrections officer suffered injuries that required surgery.
