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In page Emil Julius Gumbel:

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After the 1919 murder of prominent USPD member, Karl Liebknecht, who Gumbel greatly admired, there was strong criticism by journalist Kurt Tucholsky that the trial judge completely ignored evidence against the Nazi Brownshirts.[citation needed] Horrified, Gumbel ardently investigated many similar political murders that had occurred and published his findings in numerous publications and books, including Two Years of Murder in 1921, followed by Four Years of Political Murder in 1922, the deeply controversial Conspirators in 1924, The Armor of War of the Imperialistic States in 1928, which dealt with the causes of political murder, and Traitors fall victim to the Feme in 1929.[5]