Born Philadelphia, PA, March 4, 1864.
Died Delaware, 1954.
Pinkerton Detective Francis P. Dimaio performed critical roles in the resolution of a number of high-profile cases from 1890 through 1920. (The photo at right was taken during his retirement, when Wild West historian James D. Horan documented Dimaio's contributions to law enforcement in several books.)
Dimaio's most recognized role was as a member of the "Who are those guys?" band that pursued Wild Bunch leaders Butch Cassidy and the Sundance Kid. Dimaio's pursuit occurred in South America, and it appears unlikely that he was ever within practical reach of Butch and Sundance. The detective was in Argentina on another matter when word came that the two outlaws had also arrived in that country.
Dimaio mobilized local law enforcement and plastered Wanted posters everywhere. Butch and Sundance fled into the jungles as the rainy season arrived to prevent any pursuit. As conditions improved, word came out of Bolivia that the two outlaws had been shot to death.
But Dimaio's more significant efforts were against the Mafia in the United States. He went under cover, posing as an apprehended Sicilian counterfeiter, into the Orleans Parish Prison to learn the story behind the 1890 assassination of New Orleans Police Chief David Hennessy. Demaio succeeded in extracting useful information from one of the gunman. Terribly under weight and very ill from the conditions in the prison, Dimaio was removed from the prison as the case against the Hennessy assassins began. He needed more than a year by the ocean in Atlantic City, NJ, before he was again fit for assignment.
Later on, Dimaio contributed to the break up of a Mafia blackmailing operation in the western Pennsylvania and Ohio region (see Oldfield). He made it a point to learn Mafia methods and customs from Sicilian sources and used that information to infiltrate Mafia units in the U.S. As a regional supervisor of the Pinkertons, Dimaio supervised a group that aggressively targeted Mafia kidnapping in the Midwest.
Dimaio eventually retired from the Pinkerton Detective Agency to start his own private detective firm in Philadelphia. He lived to a ripe old age, retiring to a hotel in Delaware. History lost track of him there, but evidence suggests he died in 1958 at the age of 94.
Read more about Dimaio in:
Deep Water: Joseph P. Macheca and the Birth of the American Mafia.