James "Killer" Cunniffe (June 10, 1895 - October 31, 1926) was an American armed robber who planned and successfully carried out the 1926 New Jersey mail robbery, one of the most well-publicized thefts during the 1920s.
On October 14, 1926, he and seven others armed with submachine guns hijacked a U.S.
mail truck in Elizabeth, New Jersey and escaped with $161,000.
During the gunbattle with the guards, the driver was killed while his assistant and a local police officer were wounded.