Allan Pinkerton 
Mississippi Outlaws and the Detectives: Don Pedro and the Detectives; Poisoner and the Detectives 

Allan J. Pinkerton was a Scottish American detective and spy, best known for creating the Pinkerton National Detective Agency. Pinkerton produced numerous popular detective books, ostensibly based on his own exploits and those of his agents. Some were published after his death, and they are considered to have been more motivated by a desire to promote his detective agency than a literary endeavour.