Erich Mielke was a SED leader and head of the STASI: 
The Dark Legacy of East Germany’s Fearsome Surveillance State
 Following the end of World War II in 1945, Mielke returned to the Soviet Zone of Occupied Germany, which he helped organize into a Marxist–Leninist satellite state under the Socialist Unity Party (SED). The Stasi under Mielke has been called by historian Edward Peterson the "most pervasive police state apparatus ever to exist on German soil". During the 1950s and 1960s, Mielke led the process of forcibly forming collectivised farms from East Germany's family-owned farms, which sent a flood of refugees to West Germany. In response, Mielke oversaw the 1961 construction of the Berlin Wall and co-signed standing orders for the Border Guards to use lethal force against all East Germans who attempted to commit "desertion of the Republic".