Longtime congressional aide Justin Walling has joined the prosecutoral staff of District Attorney General Lisa Zavogiannis.“We’re happy to have him on board,” Zavogiannis said in hiring the new prosecutor who will work as an assistant district attorney. “He is a welcome addition to our staff.”Walling, who hails from Spencer, will prosecute cases in both Warren and Van Buren counties which together make up the 31st Judicial District which Zavogiannis serves. Walling is filling the opening left by former prosecutor Bill Locke, who left in January to take the job of General Sessions Judge.