MARTINSBURG, W.Va. (AP) - Three people have pleaded guilty to charges stemming from a multistate heroin trafficking operation.Thirty-four-year Jeffrey David Murphy of Martinsburg pleaded guilty on Tuesday to aiding and abetting charges, along with using a telephone to facilitate the distribution of heroin.Twenty-four-year-old Veronica Thomas of Chambersburg, Pennsylvania, pleaded guilty to one count of conspiracy to distribute heroin.Twenty-eight-year-old Cameron Stinebaugh of Berkeley Springs pleaded guilty to an aiding and abetting charge.U.S.