Erich Mielke, who died in Berlin on May 22nd, aged 92, was feared and hated more than any other man in communist East Germany.
As minister for state security from 1957 until the regime's collapse in November 1989, he commanded a network of 92,000 professional spies and 170,000 voluntary informers and part-time snoops.
Those identified as critics of the system could face imprisonment and torture, including fatal exposure to radiation. Pedantic, bureaucratic and humourless, he was viewed by many as an unprincipled, heartless party functionary, whose actions were motivated by nothing nobler than a desire to keep himself and his cronies in power.
In fact, he was a life-long communist, whose political biography was shaped by his experience in the early decades of the last century.
Born in the working-class Berlin district of Wedding, he had a tough childhood, made grimmer by the early death of his mother. Like many of his neighbours in "red Wedding", his father favoured the communist KPD over the more moderate Social Democrats, and Erich Mielke himself joined a communist youth group at the age of 12.
As a gifted schoolboy, he won a state scholarship to one of Berlin's most prestigious schools but dropped out after only two years when his teachers told him that the educational deficit caused by his underprivileged background could not be overcome. The experience further radicalised the young communist and, when the KPD set up a paramilitary group for "party self-defence", he was among the first to join.
On August 9th, 1931, he shot dead a policeman during a demonstration in the centre of Berlin. Aged only 23, he escaped to Belgium using identity papers supplied by the Soviets and, nine years later, went to the Soviet Union.
Trained as a professional revolutionary at the Lenin school, he returned to Germany after the second World War and, with other German communists who had spent the war years in Moscow, helped to establish the German Democratic Republic.
From the moment he took charge of the Stasi in 1957, the agency out-performed most of its western rivals.
East Berlin planted an agent in the office of West German chancellor Willy Brandt and, as the German public has discovered in recent months, its agents knew more about Helmut Kohl's financial misdemeanours than most of the former chancellor's closest aides.
On November 13th, 1989, as easterners streamed westwards through the newly-opened border, he attempted to justify himself with the words "but I love everybody".
He spent five months in prison on remand after he was charged in connection with the wall shootings, but his trial was postponed so he could be charged with the 1931 murder. He served four years of a six-year sentence for that crime, but was later judged too senile to face trial for his actions as a leader of the East German regime.
After his release in 1998, he moved into a flat in a high-rise building in an eastern Berlin suburb with his wife, Gertrude, where he remained until his recent move to the nursing home where he died.
He admitted in 1993 that he felt his life had been wasted.
"Millions have died for nothing," he said. "Everything we fought for - it has all amounted to nothing."
Erich Mielke: born 1907; died, May 2000.