On December 20, 1973, Cain was killed by masked gunmen in Rose’s Sandwich Shop in Chicago. Witnesses reported that no more than 15 minutes before the attack Cain had been talking with four other men who were not present when the gunmen arrived. Two of these four men were reported to have left using a back door. At the time of the gunmen’s arrival, Cain was seen talking with an unidentified woman in black. The gunmen carried a shotgun, a pistol, and a two-way radio that they used to communicate with an outside lookout. They ordered the shop’s staff and patrons (including Cain) against the wall but did not speak directly to Cain. They asked several of them if they had any money and asked, “Who’s got the package?” Cain was approached, pulled slightly away from the wall, and shot in the head with the shotgun. As he fell, the second gunman also shot him in the head. Cain’s assailants reportedly removed an item from one of his pockets before fleeing. The unidentified woman apparently left at the same time as the gunmen.