A Lancaster man has been sentenced in Rock Hill General Sessions Court to 15 years in prison for killing a man in 2016 over an of ounce of marijuana. Ernest Markevius Thompson, 23, of the 2100 block of Pheasant Drive, was sentenced to 15 years without parole after pleading guilty to voluntary manslaughter Monday in the May 2016 shooting of 20-year-old Isaiah Shinn, according to 16th Circuit Deputy Solicitor Willy Thompson.