Arnold’s treasonous plan was uncovered on September 3, 1780
One of the interesting facts about Benedict Arnold and Peggy Shippen is that Arnold’s treasonous plan was uncovered on September 3, 1780. On August 30, Arnold sent a letter to André accepting Clinton's terms and proposing a meeting through still another intermediary: William Heron, a member of the Connecticut Assembly whom he trusted. In an ironic twist, Heron went to New York oblivious of the letter's significance, and offered his own services as a spy to the British. He then returned to Connecticut, skeptical of Arnold's motives, and gave the letter to the commander of the Connecticut militia. General Parsons set it aside, interpreting it as a coded business dialogue. Four days later, Arnold used the services of a prisoner of war's wife to send a ciphered letter with similar content to New York. A meeting was eventually scheduled for September 11 near Dobb's Ferry. This meeting was disrupted when British gunboats in the river fired on his boat, unaware of his planned arrival.
On September 21, Arnold and André finally met at the Joshua Hett Smith House. James Livingston, fired on the HMS Vulture, the ship scheduled to transport André back to New York. The captain, Andrew Sutherland, received a splinter in his nose as a result of this battle, but the splinter caused the Vulture to retire, forcing André to return to New York by land. Arnold created passes for André to allow him to cross through the lines, as well as plans for West Point.
They discovered the papers exposing the West Point conspiracy and forwarded them to their superiors, but André persuaded the unsuspecting Colonel John Jameson, to whom he was transferred, to send him back to Arnold at West Point, but he never arrived. Major Benjamin Tallmadge was a member of the Continental Army's Culper Ring, a spy network established under Washington's instructions, and he requested that Jameson have the prisoner intercepted and returned. Jameson reluctantly called back the lieutenant who had been delivering André to Arnold's custody, but he then dispatched the same lieutenant as a messenger to inform Arnold of André's arrest.
