Question: What is a massacre that occurred as part of an attempt to free a federal prisoner was Vernon C. Miller a gunman in?
Sentence (from "Vernon C. Miller"): Vernon C. Miller (August 25, 1896 – November 29, 1933) was a freelance Prohibition gunman, bootlegger, bank robber and former sheriff in Huron, South Dakota, who, as the only identified gunman in the Kansas City massacre, was found beaten and strangled to death shortly after the incident.
Relevant evidence: Yes