LINCOLN, Neb. (AP) — Nebraska prisoners who assault a guard or another inmate could soon lose up to two years’ worth of “good time” credit, which reduces the time they spend behind bars.

Gov. Dave Heineman said Tuesday he has approved a rule change that doubles the amount of credit prisoners could lose for misbehavior. It goes into effect Saturday.

Heineman announced plans for reform shortly after the arrest of Nikko Jenkins, who is accused of four Omaha-area slayings after his release from prison. Jenkins had threatened violence while incarcerated and begged corrections officials to commit him to a mental health institution.

Heineman says he has done everything that he can do administratively. He called on lawmakers to enact reforms that require violent offenders to earn good time instead of receiving it automatically.