The Death squad is further referenced in Martyrs of the Spanish Civil War .
see also Saints of the Spanish Civil War ) .The Republican death squads were heavily staffed by members of Joseph Stalin 's OGPU and targeted members of the Catholic clergy and the Spanish nobility for assassination ( see Red Terror ( Spain ) ) .According to author Donald Rayfield , `` Stalin , Yezhov , and Beria distrusted Soviet participants in the Spanish war .