One of the three people convicted in the so-called “Facebook Murders” case in Jonesborough has agreed to a plea deal with a lower prison sentence after she was granted a new trial.Barbara Potter pleaded guilty to two counts of involvement in first-degree murder and had her previous sentence of life in prison reduced to 25 years, according to Assistant District Attorney Dennis Brooks.Potter will also be eligible for parole, but whether she gets it will be up to the parole board.