Then he observed that it was possible that they belonged to three Tories who had joined Ferguson’s force.

From The Road to Guilford Courthouse by John Buchanan. Page 205.

“But Patrick Ferguson did begin to suspect that he was the victim of a ruse. His men were in need of meat, and so he took a force into the field to search for Rebel cattle. Accompanying him was the noted Indian fighter Captain— later Colonel—John Carson, one of the men who had agreed to Charles McDowell’s policy. They found a large herd roaming in the cane-breaks. Ferguson’s men assumed that the cattle belonged to Rebels and began slaughtering them. John Carson, who knew who owned the cattle, watched without comment until over 100 head had been slaughtered. Then he observed that it was possible that they belonged to three Tories who had joined Ferguson’s force. The upshot of this incident was that the owners of the cattle, loyal Tories all, were incensed, the Rebels made sure that the story was spread abroad, and Patrick Ferguson realized that he had been outwitted. But John Carson’s good name, temporarily sacrificed for the cause, was not easily recovered. Many years after the Revolution a man charged that John Carson had been a Tory. John Carson’s son, Samuel, a member of Congress, thereupon challenged the slanderer to a duel and killed him.