100-year-old Benjamin Ferencz is a lawyer, writer, thinker and pacifist who investigated Nazi war crimes after the Second World War, and is the last surviving prosecutor from the Nuremberg War Crimes Trials.
He was chief prosecutor for the US Army at the Einsatzgruppen Trial, one of the 12 military trials held by the US authorities at Nuremberg in Germany from November 1945 to October 1946.
He later became an advocate for the establishment of an International Criminal Court to make war criminals accountable for their actions.
Listen to the full interview with Benjamin Ferencz
In his book Parting Words: 9 Lessons for a Remarkable Life he shares his extraordinary life story and some of the things he has learned along the way.
He was also the subject of the 2018 documentary Prosecuting Evil.
He says he first heard about the Einsatzgruppen when one of his researchers came to him at the Berlin office where he was investigating war crimes with a bundle of papers he had come upon.
The title of this document translated as Situation Reports from the Soviet Union – a banal title concealing documentation of appalling brutality - was a top-secret report to the Gestapo from the Einsatzgruppen.
"Their principle assignment was to kill all the Jews that existed anywhere. Whenever they entered a territory the German army had reached, the Einsatzgruppen went in to play and they murdered without pity or remorse every single Jewish man, woman and child.
"And then they reported that to Berlin, Berlin consolidated these reports into a combination of the four different Einsatzgruppen that existed A, B, C and D covering different terrains and they circulated that to about 99 distribution lists, 99 leaders of the Nazi Party and Nazi hierarchy."
Ferencz says he sat down with a small adding machine and set about the grim task of adding up the dead.
"When I reached a million people murdered by these Einsatzgruppen I took the next plane from Berlin to Nuremberg where General (Telford) Taylor was busy setting up the new trials and I said we better put on another trial. He said we can’t the Pentagon has already approved the budget, we’re already assigned all the lawyers, we’ll never get approval for another trial."
Ferencz was indignant:
"I said ‘you can’t let these bastards go, I have in my hand clear cut murder of a million people and I have the name of their commander, I have this official Top Secret report to Berlin.
"He said can you do it in addition to your other responsibilities?"
Ferencz was duly appointed as chief prosecutor "for what turned out to be the largest murder trial in human history."
He concluded his case in two days, and all 24 Einsatzgruppen leaders were convicted.
Ferencz called no witnesses, he had no need to, the Nazis kept scrupulous records, he says.
The best evidence is documentary evidence, Ferencz says.
"I could have called ten witnesses, they could have given ten different descriptions, I didn’t need that.
"I had the best available record which was their top-secret report to their superior officers."
The chief defendant in the trail was a man called Otto Ohlendorf.
"Otto Ohlendorf was the father of five children, he was an intelligent, well-educated man and when asked did he agree that his unit had killed 90,000 Jews, he said ‘No I can’t agree to that.’
"I said, ‘why not?’ he said well the men used to brag about the money count, so usually it was inflated a bit, but 60,000 to 70,000 that would likely be a more accurate figure."
Some of the people carrying out these mass murders were so enthused by their work that they bragged to inflate the number killed.
"Later they would say they were against it and so on… baloney - they went to their job with full joy."
He spoke with Ohlendorf privately once he had been sentenced to death, Ohlendorf said the massacres were a pre-emptive attack as Germany was at threat from Russian invasion.
Ohlendorf was hanged in 1951.
Einsatzgruppen didn’t act alone, he says, they had willing collaborators.
"They would have done it even without help but they welcomed the help.
"Antisemitism wasn’t something which suddenly popped up, it’s been a tradition for centuries as well."
The Nazis in a way were opportunistic, he says.
"The people in Lithuania and Romania and other countries they came out to watch the killing in many cases, I’m not saying every person in that country was an anti-Semite, that would not be correct, but many of them were."
After the war Ferencz was involved in arranging compensation for Jews who survived the war and was instrumental in the establishment of the International Criminal Court.
"This [Trump] administration, which I am happy to say is going out, has tried to sabotage the International Criminal Court, they invited me to come and make a closing statement in their first trail."
Ferencz, who was born into poverty to parents who fled persecution in Europe, has dedicated his life to international law and justice.
"Nobody pays me, I don’t represent anybody, I represent suffering humanity."