The Mexican Revolutionary General Pancho Villa, who had at one time been supported by the United States, felt betrayed when the Americans backed Carranza. In January 1916, Villa's followers, known as Villistas, attacked a train and killed 16 American businessmen who were aboard. Two months later Villa's men crossed the border into the United States and attacked the town of Columbus, New Mexico, killing an additional 19 Americans. Following these attacks, General Pershing took his forces into Mexico to pursue Pancho Villa.