The British forces arrived in the valley on June 30, having alerted the settlers to their approach by killing three men working at an unprotected gristmill on June 28. The next day, Colonel Butler sent a surrender demand to the militia at Wintermute's (Wintermoot) fort. Terms were arranged in which the defenders would surrender the fort with all their arms and stores and would then be released on the condition that they not bear arms again during the war. On July 3, however, the British saw that the defenders were gathering in great numbers outside of Forty Fort. William Caldwell was engaged in destroying Jenkin's fort with the American militia a mile away, so Butler organized an ambush. He ordered Fort Wintermute to be set on fire, and the Patriots believed that it signified a British retreat and advanced rapidly. Butler told the Seneca to lie flat on the ground so as not to be seen. The militia advanced to within a hundred yards of the British rangers and fired three volleys at them. The Seneca rose to their feet, fired one time, and then charged to engage in hand-to-hand combat.