 Complete the following phrase:  Following Pinkertons service with the Union Army, he continued his pursuit of train robbers, including the Reno Gang. He was hired by the railroad express companies to track outlaw Jesse James, but after Pinkerton failed to capture him, the railroad withdrew their ficial support and Pinkerton continued to track James at his own expense. After James allegedly captured and killed one of Pinkertons undercover agents who was working undercover at the farm neighboring the James familys farmstead, he abandoned the chase. Some consider this failure Pinkertons biggest defeat. He also opposed labor unions. In 1872, the Spanish Government hired Pinkerton to help suppress a 