Thirteen years after the slaying of a Gainesville woman, her killer has been convicted of murder and sentenced in Hall County Superior Court. Daniel Lee Mason III entered a plea of guilty but mentally ill to malice murder, two counts of felony murder and aggravated assault in the April 1, 2001, death of Crystal Star Barnette, 37. He pleaded guilty to the charges on April 15, less than one week after being found mentally competent to stand trial.