Authorities have arrested a man in the shooting death of a witness in a Columbia County murder case. Officials say 32-year-old William Cooksey Roberson is jailed on a first-degree murder charge in the death of 35-year-old Roger Williams, 35. Roberson`s bond was set at $150,000. Williams was a potential witness in a case against 17-year-old Justin Vansickle, who is charged with the May 12th murder of 42-year-old Mark Randall Byrd at Byrd`s home in the Ebenezer community. Sheriff Calvin Knighton said investigators have not determined, however, if Williams` shooting death had anything to do with the Vansickle case.