Conan Doyle had met Allan Pinkerton on an ocean voyage, where the writer became fascinated by the "singular and terrible narrative" of the Molly Maguires. Later, however, "Allan Pinkerton's and Arthur Conan Doyle's friendship ended over the rendition of some Pinkerton exploits in fictional form ..." Patrick Campbell, a relative of one of the executed Mollies, who wrote "A Molly Maguire Story", learned from a McParland relative that McParland's two brothers, Edward and Charles, also went undercover against the Mollies. Campbell speculates that the break between Pinkerton and Conan Doyle may have resulted because,