Tom Horn see as a warning. During the Wilcox train robbery investigation, Horn obtained information from Bill Speck that revealed which of the robbers had killed Sheriff Josiah Hazen during their escape. Either George Curry or Harvey "Kid Curry" Logan were said to have killed the sheriff. Both outlaws were members of Butch Cassidy's Wild Bunch gang, then known as "The Hole-in-the-Wall Gang" after their hideaway in the mountains. Horn passed this information on to Charlie Siringo, who was working the case for the Pinkertons. Horn briefly entered the United States Army to serve during the Spanish–American War as the chief packer
Butch Cassidy and the Sundance Kid says he wrote the story as an original screenplay because he did not want to do the research to make it authentic as a novel. Goldman later stated: The whole reason I wrote the ... thing, there is that famous line that Scott Fitzgerald wrote, who was one of my heroes, "There are no second acts in American lives." When I read about Cassidy and Longbaugh and the superposse coming after them—that's phenomenal material. They ran to South America and lived there for eight years and that was what thrilled me: they had a second act. They were more legendary