Who led XXX?
NKVD
Until the reorganization begun by Nikolai Yezhov with a purge of the regional political police in the autumn of 1936 and formalized by a May 1939 directive of the All-Union NKVD by which all appointments to the local political police were controlled from the center, there was frequent tension between centralized control of local units and the collusion of those units with local and regional party elements, frequently resulting in the thwarting of Moscow's plans.
Nikolai Yezhov