GLENWOOD SPRINGS, Colorado — Heath Johnston was sentenced to 48 years in the Colorado Department of Corrections for the killing of his brother, Sam Johnston.

Heath Johnston, 21, admitted to killing his brother and pleaded guilty to second-degree murder, as part of a plea deal offered by prosecutors, two days before his first-degree murder trial was set to begin in September.

Prosecutors agreed to charge Johnston with the lesser charge in exchange for a guilty plea and the maximum sentence of 48 years in prison, which Johnston received Wednesday in Garfield County District Court.

Johnston was credited for 661 days which he spent incarcerated at the Garfield County Jail since his arrest in December 2008. The court also ordered a mandatory five-year parole period for Johnston when he is released around 2056. Johnston will be 68 years old.

Johnston was arrested in December 2008 after shooting his brother in the back of the head with a shotgun, while Sam sat on a couch at his Rifle residence. If convicted of first-degree murder, Johnston faced life in prison.

The three-week trial was scheduled to begin in September but was vacated when Johnston agreed to the plea deal.