During WWI, Luxemburg and Liebknecht formed a revolutionary, antiwar socialist group in Germany that became the Spartacus League. After the proclamation of the German republic in 1918, they opposed the moderate government formed by the Social Democrats and advocated its violent overthrow, to be replaced by a dictatorship of the proletariat. They transformed their league into the German Communist Party and led an uprising, which was crushed. Arrested, they were murdered by whom while in custody? Discuss
Source: The Free Dictionary