Benedict Arnold insisted on a personal meeting with John Andre. Knowing such a meeting would require him to go behind enemy lines, Andre initially resisted but finally gave in. He would wear his uniform, however. To dress in disguise, or use a false name, would automatically render him a spy, if he were caught.
The meeting with Arnold (on September 21, 1780) took longer than expected, but Andre left with priceless documents. Benedict Arnold gave him key data about West Point, including troop placement.
Because his ship (the Vulture) had moved up river, Andre was stranded. He would have to return by land, inside American lines.
Against his better judgment, Andre removed his uniform, wore a disguise and used passes (prepared by Arnold) in the name of John Anderson. Joshua Smith, an associate of Arnold, traveled with him.
Believing he was safe (once the two men reached neutral territory on September 23rd), Andre continued alone. By 9 am that morning, he was apprehended by suspicious militiamen. Searching Andre, the men found the West Point documents in Andre's boot.
It was the beginning of the end for John Andre.