Jürgen Mossack is at the heart of the biggest financial data leak in history, and has allegedly been helping world leaders, politicians and celebrities launder money, dodge sanctions and evade tax from his base in Panama.
It has now been revealed that his father, Erhard Mossack, was a member of the Nazi fighting unit known as the 'Death's Head division', a dreaded force during the Second World War.
Today, his half-brother Horst, has spoken of his 'shock and bewilderment' at the news of the unmasking of his half-brother.
He described the twisted family history that led to the estrangement of the siblings, both of whom raised by a man who not only fought with the Nazis but later joined the CIA to carry out espionage on Cuba.
The 68-year-old Horst last saw his sibling Jürgen 60 years ago when he left the town of Fürth in Bavaria bearing the name of his father Erhard.
Now living in the Black Forest region of Germany, Horst was born out of wedlock to a woman called Luisa Herzog.
'This was shameful in those days so I was put up for adoption,' he told MailOnline. 'My mother later went on to marry Erhard Mossack. I took that name later.
'What has come out of Panama is shocking news, astounding, bewildering even, but I can't say I feel shame because I have no connection in reality with him.
'I left all those years ago and we never had contact again. He was just a child, so how can I say what I remember of him? All I know is that I heard that he went to London and lived there for quite some time.
'He has a brother called Peter and a sister called Marion in Germany. Both my mother and their father are now dead.
'I remember that Erhard Mossack, their father, was in the S.S. I believe after the war he became a journalist.'
German media have reported that Erhard served as a Rottenfuehrer - roughly corresponding to a senior corporal - in the Waffen, or fighting arm, of the dreaded
The Sueddeutsche Zeitung in Munich, one of the publications in the global alliance of newspapers which unmasked the activities of Jürgen Mossack's firm in Panama, said Erhard served in a 'Death's Head' unit of the S.S.
These were the units which ran the concentration camps. But if he was in the Waffen S.S. it probably meant he served in the Third Waffen S.S. Panzer Division Totenkopf.
Most of the division's initial enlisted men were recruited from concentration camp guards and others were members of militias that had committed war crimes in Poland.
Due to its insignia, it was sometimes referred to as the 'Death's Head Division'. Members of the division committed war crimes - one of them against British soldiers.
The Le Paradis massacre was carried out by members of the 14th Company of the division.
It took place on May 27 1940, during the Battle of France, at a time when the British Expeditionary Force was attempting to retreat through the Pas-de-Calais region during the Battle of Dunkirk.
Soldiers of the 2nd Battalion, the Royal Norfolk Regiment, had become isolated from their regiment. They occupied and defended a farmhouse against an attack by Waffen S.S. forces in the village of Le Paradis. After running out of ammunition, the defenders surrendered to the German troops.
But the Germans machine-gunned the men after surrendering, with survivors killed with bayonets. Two men survived with injuries, and were hidden by locals until they were captured by German forces several days later.
According to the Sueddeutsche, Erhard was captured by the Americans in Munich after the war with a list of Nazi 'Werewolf' members upon him.
The Werewolf units were intended to fight on as a guerrilla force after the surrender, but this never happened.
The newspaper said it applied to the German Federal Intelligence Service, the BND, for information about him. The BND confirmed documents existed on him but said they would not be released becauve this could endanger 'the well-being of the Federal Republic of Germany or one of its members'.
In 1948 he left Germany with his family to settle in Panama, and later returned to Munich with his wife during the 70s. He died in the 1990s, his wife followed five years ago.
According to reports, U.S. Army intelligence archives hold a file on him as he allegedly offered his services to the U.S. government as an informant, claiming 'he was about to join a clandestine organisation, either of former Nazis now turned Communist... or of unconverted Nazis cloaking themselves as Communists.'
An Army intelligence officer wrote that the offer to spy for the U.S. might simply be 'a shrewd attempt to get out of an awkward situation'.
Nevertheless, the old intelligence files indicate that Mossack's father later ended up in Panama, where he offered to spy, this time for the CIA, on Communist activity in nearby Cuba.
The children Peter and Marion returned to Germany in the 1970s; brother Peter is the Honorary Consul for Panama based in Frankfurt.
In 1952 a book by Erhard Mossack was published in Germany called The Last Days of Nuremberg, detailing the capture of the city to American forces in 1945.
Horst Mossack says he believes the father of Jürgen was the author.
He added; 'I don't expect I will ever see Jürgen again. If I did I would ask him exactly what went on.'
Meanwhile, the second man behind the Panama firm, a lawyer named Ramon Fonseca Mora, has been revealed to be an award-winning novelist famous for his salacious plots.
As a young man Fonseca reportedly wanted to be a priest, before age and materialism took over. On joining forces with partner Mossack, he told a journalist in 2012, 'Together, we have created a monster.'
In among accounts he follows on Twitter are a fair amount of 18+ accounts - at first glance the naked bottom of 'Horny Cherry' sits alongside the official account of the President of Argentina Mauricio Macri.
Fonseca is currently on a leave of absence, according to the ICIJ, which is part of 100 outlets to have worked together on the leak.
This article originally appeared in the April 4, 2016 number of the Daily Mail.