<P> At first, Woodhull would go to New York City every few weeks to gather intelligence . His married sister Mary Underhill lived there, giving him a reason to visit . On October 31, he was questioned at a British checkpoint, increasing his anxiety about the dangerous mission . Nonetheless, he returned to Setauket with valuable information about the British supply fleet . On November 23, 1778, Woodhull provided a precise report on the identity of British units and the numbers of troops and dispositions in New York City, proving his worth as a spy . Woodhull soon recruited his brother - in - law Amos Underhill to gather intelligence, who ran a boarding house in the city with his wife Mary, but Underhill's reports were often too vague to be of much value . </P> <P> At first, Woodhull had to return to Setauket to pass messages to Caleb Brewster, which he would take to Tallmadge, or to receive messages from Tallmadge via Brewster . By December 1778, Tallmadge set up couriers, at first Jonas Hawkins, then in the early summer mainly Austin Roe, who would take messages the 55 miles (89 km) between New York and Setauket to pass them to Brewster . The courier's task was to get the letters to Brewster who would pick up messages at one of six secluded coves near Setauket and, with his rotating whaleboat crews, take them across the Sound to Tallmadge at Fairfield, Connecticut . Tallmadge would then take them to Washington's headquarters . This time - consuming task was replaced in January 1779 by the assignment of express riders to take the messages from Tallmadge to Washington . </P> <P> Local tradition claims that Anna Strong, a resident of Setauket and a friend and neighbor of Abraham Woodhull, helped pass along messages from the spy ring by posting pre-arranged signals to indicate when one of the spies was ready to submit intelligence . If Strong hung a black petticoat on her clothesline, it meant that Brewster had arrived in town in his whaleboat . Next to that, she would hang a quantity of white handkerchiefs . The specific number of handkerchiefs indicated one of six hiding places where Brewster might be located . Woodhull used Strong's signals to meet Brewster or to drop messages at one of the meeting places . Historian Richard Welch writes that the tradition of the clothesline signal is unverifiable, but it is known that the British had a woman at Setauket under suspicion for disloyal activities who fits Anna's profile . </P> <P> Brewster occasionally would add his own report to the Culper messages . In a January 1779 report received by Washington in early February, Brewster sent some information about naval matters and boat building at New York City and warned that local Loyalists were outfitting privateers for operations on Long Island Sound . </P>

Who was culpers gang how did they help the revolution