Born Philadelphia, PA, March 4, 1864.
Died Delaware, 1954.
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.
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.