Jacob McCoy was the son of Asa Harmon McCoy and Nancy Cline. His father was one of the first casualties in the Hatfield and McCoy feud. Ruth's sister Nancy, married Jacob's brother Asa H. McCoy.
Harmon, a younger brother of Randolph McCoy, waited two years to choose sides, stayed home and worked his farm. He joined the Union Army in an area where most of the men joined the Confederate. When he returned home wounded he was given the cold shoulder by his family and neighbors.
Jim Vance, uncle to Devil Anse Hatfield, told him that the Logan Wildcats would be paying him a visit. So Harmon hid out in a cave. The partisans traced Pete's footsteps through the snow and found Harmon, lame and suffering from lung fever and killed him. It is believed that Jim Vance did the actual killing but was never brought to trial.