Treachery of Benedict Arnold
Through the Tory messenger Joseph Stansbury, Benedict Arnold established communications with Captain John Andre, British General Henry Clinton's aide, on 10 May 1779. For the next 16 months he conspired with the British by providing information in return for an agreement of money and a position in the British Army.
In all, his traitorous acts included divulgence of Washington's plan for the Yorktown campaign, intelligence concerning the strengths and weaknesses of the American Army, and a plot to surrender West Point to the British, as Arnold had received command of that post on 3 August 1779.
On 23 September 1779, volunteer patriot militiamen captured the British Captain John Andre with several incriminating documents from Arnold. These papers detailed the defenses at West Point and provided valuable intelligence information about the American Army. Also, Andre admitted under interrogation that he had been involved in espionage with an undisclosed American traitor.
Arnold learned of the capture of Andre before Washington had been informed, and he quickly withdrew north on the Hudson River to evade his own capture. Upon receiving both the captured documents from Andre and a report of his confession to espionage, Washington realized that he had been betrayed. Expecting imminent danger of a British attack on West Point, he quickly moved to fortify it. However, a British attack on West Point never came.
Although the attempt to capture West Point had failed, the British compensated Arnold for his property losses and commissioned him as a Brigadier General of the British Army. He was given a command and raised a legion of Tories and deserters, which he led on raids against the Americans in 1781. However, the British leadership on all levels distrusted the traitorous Arnold and he decided to move to London that December. Soon after that, he left military service to become a merchant-shipper in New Brunswick. He moved to Canada in 1787, but finally returned to England in 1791.
Benedict Arnold fell into depression during his later years, finally being afflicted by a "nervous disease" which took his life in 1801. He died a wreck of a man, leaving only debts and lawsuits to his family upon his death.