On Saturday , 23 September AndrÃ was captured , near Tarrytown , by three Westchester patriots named John Paulding , Isaac Van Wart and David Williams ; the papers exposing the plot to capture West Point were found and sent to Washington , and Arnold 's treachery came to light after Washington examined them . On Saturday , September 23 , AndrÃ was captured , near Tarrytown , by three Westchester patriots named John Paulding , Isaac Van Wart and David Williams ; the papers exposing the plot to capture West Point were found and sent to Washington , and Arnold 's treachery came to light after Washington examined them .