Jurors learned Friday that the gun used to kill a Greenbriar Trail man June 30, 2013, was never found. The murder trial of Tarell Momon, 36, an inmate at Dooly State Prison, and Terrance Ray Griswould, 30, of Augusta, both charged in the "hit style" killing of Michael Anthony Riley, 51, of Greenbriar Trail, began Friday. Riley's wife, Antoinette Braddy Riley, 50, of Greenbriar Trail, and her daughter Katrina Denise Ledford, 31, of Davisboro, each pleaded guilty earlier this year to murder charges and are expected to testify as the trial continues this week.