Eighty-nine-year-old John Demjanjuk takes the stand on Monday over the gas chamber deaths of thousands of Jews in what will likely be the last major Nazi war crimes trial.
The Ukrainian-born Demjanjuk is expected to be pushed into the Munich court in a wheelchair to face 27 900 individual charges of assisting murder while a Nazi guard at the Sobibor death camp in occupied Poland between March and September 1943.
If found guilty the infirm old man will almost certainly spend the rest of his life in prison. If cleared, he will face a trial of a different kind as he has no passport and no country wants him.
Demjanjuk, who was deported from the United States in May after a decades-long cat-and-mouse game with justice and has already been sentenced to death once in Israel in a separate case, denies all charges.
He denies even being at Sobibor, where an estimated 250 000 men, women and children went to their deaths in the gas chambers.
Prosecutors have an SS identity card bearing Demjanjuk's name and his transfer orders from Trawniki, a sadistic training camp for Nazi guards, to Sobibor.
He says he was a Red Army soldier captured in 1942 by the Germans and then moved around various prisoner-of-war camps. After the war, he moved to the United States, where he was a car worker in Ohio.
"We know in our hearts that my dad never harmed anyone. And we know based on the evidence that there is absolutely no evidence that he harmed even one person," his son, John Demjanjuk Jr., told AFP.
Demjanjuk's lawyer, Ulrich Busch, said that even if it could be proved his client was at Sobibor, he would have been there under duress and can not now be held responsible for the atrocities carried out there.
Courts in Israel and the United States have already established he was in Sobibor.
Demjanjuk, who turns 90 in April, is suffering, his family says, from a litany of health complaints, including bone marrow disease and blood infections, and is confined to a wheelchair.
The defence team has called for the trial to be shortened and held behind closed doors due to Demjanjuk's susceptibility to infection, according to documents obtained by AFP.
"They've accelerated his death... he's not going to survive this," his son said.
Medical experts have nonetheless judged him fit to stand trial, but proceedings will be limited to two 90-minute sessions per day.
If convicted, Demjanjuk faces the rest of his life behind bars, said Jonathan Drimmer, a US lawyer who was lead prosecutor against Demjanjuk in 2002 when he was stripped of his US citizenship for lying about his wartime past.
"Whether it's 20 years in prison or a life sentence, I would imagine a very serious and lengthy criminal penalty," Drimmer told AFP.
Less clear is what would happen to the father-of-three if he were acquitted. Without his US citizenship, he effectively has nowhere to go.
"He falls into this grey zone of a stateless person and it isn't clear where he would end up," said Drimmer.
More than thirty co-plaintiffs, many of them Dutch, are also due to testify.
The majority of these lost family members in the gas chambers of Sobibor, described by the US Office of Special Investigations as "as close an approximation of Hell as has ever been created on this planet."
However, there are no living eyewitnesses who actually saw Demjanjuk at the camp. The prosecution will rely heavily on testimony by people who have now died.
"All I want is for justice to be done. Nothing else," Kurt Gutmann, a co-plaintiff whose mother and brother were murdered at Sobibor, told AFP.
The trial, in the southern German city of Munich, is not the first time the barrel-chested, round-faced Demjanjuk has been in the dock for war crimes.
He was sentenced to death in Israel in 1988, convicted of being "Ivan the Terrible", a particularly sadistic Nazi guard who hacked at naked prisoners with a sword as they were herded into the gas chambers.
This conviction was overturned when it emerged that Israel had the wrong man.
For Efraim Zuroff, head of the Simon Wiesenthal Centre in Jerusalem, the Jewish organisation that hunts Nazi war criminals, the trial is a seminal moment.
"He is the most wanted Nazi criminal, top of the list we publish ... we will finally know his exact role in the extermination machine," Zuroff told AFP.
For Gutmann, the trial is all about "telling my story and the story of those who are not alive today to tell it."
"We should never be allowed to forget," Gutmann said.
AFP
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