What captain in the Connecticut militia, would later commit treason and command British troops?

Benedict Arnold was a captain of the Continental Army who committed treason by giving the British our next moves. When it was known he was a traitor, he left the Continental Army to command British troops. Because he committed treason, he was unpopular in US and so he had to move to Great Britain after the war. And because the British had lost the war, Arnold was also unpopular in Britain.