NKVD troika or Special troika , in Soviet Union history, were institutional commissions of three persons who issued sentences to people after simplified, speedy investigations and without a full trial. These commissions were employed as an instrument of extrajudicial punishment introduced to supplement the Soviet legal system with a means for quick execution or imprisonment. It began as an institution of the Cheka, then later became prominent again in the NKVD, when it was used during the Great Purge to execute many hundreds of thousands of Soviet citizens.