A former Marine will spend the next 40 years in a Virginia prison after pleading guilty to first-degree murder.
Don Walker was a corporal at Cherry Point in North Carolina when he was arrested for the December 2010 murder of his girlfriend's estranged husband in Montgomery County.
Investigators say Walker broke into 25-year-old Matthew McPeak's Christiansburg home, turned off the power and ambushed him when he came home.
McPeak was stabbed repeatedly with a hunting knife.
McPeak's wife, Danielle received a 40-year sentence in May.
