On Monday in Cincinnati, the US Court of Appeals gave yet another twist to the case of John Demjanjuk, who was sentenced to death in Israel in 1987 after a war-crimes trial decided that he was 'Ivan the Terrible' - the gas-chamber operator at the Treblinka death camp in Poland during the Second World War. Amid growing concern about the evidence that led to Demjanjuk's extradition to Israel, the court ordered the four US prosecutors in his 1981 denaturalisation case to be questioned under oath by a federal judge.
Chief Judge Gilbert Merritt said that the US Department of Justice, prior to the 1986 extradition proceedings, had documents indicating that another Ukrainian, Ivan Marchenko, was Ivan the Terrible. The 'bedrock question' for the court now, he said, was whether the prosecutors' failure to disclose this information misled the court into ordering Demjanjuk's extradition.
Since the prosecutors have already admitted withholding evidence - as I reported in the Independent last December - a reversal of the extradition order is almost certain. The possibility then arises that Demjanjuk's trial, conviction and sentence in Jerusalem will be overturned, and that he will be returned to the US.
It would be wrong to blame the collapse of the case entirely, or even mainly, on the American prosecutors, and to do so would obscure the significance of the debacle for future war-crimes trials.
A number of factors conspired to make the investigation go wrong: the Soviets distrusted the Americans and used it to play politics; the Americans distrusted the Soviets and, believing passionately in Demjanjuk's guilt, played havoc with the evidence; the Israelis, seized by the same passion, could not let go. But the most important reason is that Demjanjuk told - and stuck to - two obvious lies.
In 1975 the Soviet authorities sent the Americans a list of 70 possible war criminals. Among them were Feodor Federenko, a Ukrainian suspected of being a guard at Treblinka, and Demjanjuk, thought to have been a guard at a different camp - Sobibor, also in Poland.
The US Immigration and Naturalisation Service began to question Sobibor survivors, but none of them could identify Demjanjuk. A spread of 17 photographs, including Demjanjuk's 1951 visa photograph and a picture of Federenko, was sent to Israel in April 1976. None of the Sobibor survivors in Israel could identify Demjanjuk either - but unexpectedly, several Treblinka survivors thought they recognised him as the gas-chamber guard of their nightmares.
In August 1976 the Soviets went further: a Ukrainian newspaper published a statement made 30 years earlier at a Soviet war-crimes trial by a guard from Sobibor, Ignat Danilchenko. He had stated that the man he remembered best from Sobibor was Ivan Demjanjuk, with whom he had also served at the Flossenburg concentration camp in Germany.
But Demjanjuk and his family claimed from the start that the Danilchenko testimony was a fake, and part of a Soviet conspiracy.
In 1978 the US Department of Justice set up the Office for Special Investigations to investigate suspected war criminals. The OSI was so committed to the testimony of the Treblinka survivors that Demjanjuk was Ivan the Terrible that it simply filed away the inconvenient Danilchenko.
Fourteen years later, Danilchenko's statement has become instrumental in demolishing the charge that Demjanjuk was Ivan the Terrible - while confirming that he was a guard in other camps.
The Danilchenko testimony did seem to indicate that the Soviets were focusing on Demjanjuk. 'They certainly didn't like people who had emigrated to the West, and they certainly enjoyed showing America up as a haven for war criminals,' said a former US negotiator with the Soviets. 'But I don't think this was planned. Demjanjuk probably came to their attention when, years after his arrival in the States, he wrote to his mother - who believed him dead - that he was hale and hearty in Cleveland, Ohio. And later, equally conspicuous, his wife visited her family in Ukraine.
'While it was always grotesque to suggest they specially picked out that one insignificant Ukrainian to show up those who had emigrated abroad, they no doubt used him - as they did others - when it became convenient.'
By 1979 the OSI had become a political football between right-wing politicians who wanted war-crimes prosecutions stopped, and Jewish and liberal groups who insisted they must continue. The pressure to succeed with the Demjanjuk case was enormous: winning it would justify the OSI's continued existence.
But equally, the OSI had to win because it believed so passionately in Demjanjuk's guilt. What had persuaded it, the prosecutor John Horrigan told me in 1986, 'was that Demjanjuk was a liar. By the time we went to trial in 1981, I had no doubt that he was Ivan from Treblinka - a truly terrible man.'
All along, Demjanjuk claimed that he had been a Soviet soldier from 1941, was taken prisoner by the Germans in 1942, and remained a prisoner of war until 1944, when he was drafted into the Galician Waffen SS to fight the Russians. The US investigators were convinced that this was a series of lies.
Demjanjuk had also made two extraordinary statements on official questionnaires in Germany prior to emigrating to the US. First, he had said that he lived from 1937 to 1943 in Sobibor, Poland. His later explanation was that he needed a pre-war residence outside the Soviet Union to avoid forcible repatriation. It was an impossible claim: Sobibor, an obscure spot in the Polish forest, not even marked on pre-war maps, could only have been known to someone associated with the extermination camp the Nazis built there in early 1942.
Demjanjuk's second mis-statement had an entirely harmless origin. Required to state his mother's maiden name, he simply could not remember it, so he said it was Marchenko - the Ukrainian equivalent of Smith. But his mention of that name became an essential factor in convincing the OSI of his guilt.
In June this year it was disclosed that the name Marchenko had occurred in statements by two Treblinka guards that the Soviets had sent to the OSI in 1978-79. They had testified 30 years earlier that the gas-chamber guard at Treblinka was called Marchenko.
Although Demjanjuk's SS identity card was in his own name, the OSI convinced itself that he must have used his mother's name at Treblinka. In fact her maiden name was not Marchenko at all, but Tabachyk.
However, in 1979 the OSI's suspicions were reinforced by two lists of Treblinka guards received from the Polish War Crimes Commission and from the Russians. Neither contained Demjanjuk's name, but both cited Ivan Marchenko. A subsequent letter from the Poles said that they had no record of Demjanjuk. Neither of the lists, nor the letter, was passed to the defence.
The OSI was aware of the contradictions in the evidence, but it persisted in believing that Demjanjuk had to be Ivan the Terrible: 'Prosecuting him became an obsession for all of us,' Horrigan said in 1986.
Demjanjuk became an obsession for Israel as well. The Israelis had not wanted to hold a second war-crimes trial after the trauma of the Eichmann trial in 1961. They were urged into it by the Americans, who felt that a successful trial would vindicate their work. The survivors' horrific memories, continually repeated, created a momentum, and the Israelis became as committed to Demjanjuk's conviction as the Americans.
Both the OSI and the Israelis had documents that should have thrown doubt on the possibility that Demjanjuk was Ivan the Terrible. One was a report from the Treblinka trial in Dusseldorf in the early Sixties. When an SS corporal called Gustav Munzbergher, who supervised the gas-chamber operation, was asked what had happened to the infamous Ivan, he said Ivan had travelled in his convoy to Trieste in September 1943 (when the death camp was dismantled) and had later joined the partisans.
Another document surfaced in Italy in 1986 - a letter to an Italian journalist from another Treblinka SS sergeant, Franz Suchomel, who said that Ivan worked at a rice warehouse in Trieste that served as a camp for Jews between October 1943 and May 1946, and also mentioned the rumour that he had eventually gone over to the partisans.
Finally, there was the statement by Danilchenko, who described his service with Demjanjuk at Sobibor, and later, until the end of April 1945, at Flossenburg. If Danilchenko told the truth, and Demjanjuk was at Sobibor from March 1943 and Flossenburg from March 1944, and never in Trieste, then he could not have been Ivan the Terrible.
The Danilchenko statement was never seen by the judge in the American denaturalisation trial in 1981. 'As the Soviets wouldn't let us see him, I never trusted it,' I was told by Allan Ryan, director of the OSI at that time, and one of the four lawyers the US appeal court will now question.
Demjanjuk's family turned to the powerful Ukrainian community in the US and Canada for financial and political support. Convinced that he was the victim of a Soviet conspiracy, supporters contributed dollars 2m for his defence. For them, the case became a crusade, with Demjanjuk a symbol of Soviet and Jewish persecution.
The core of the problem, however, is why so many survivors of Treblinka identified Demjanjuk as Ivan the Terrible. It is true that Demjanjuk, in his 1951 visa photograph - taken when he was 31 - does superficially resemble Marchenko at 30. But this alone does not explain the survivors' errors. The truth is that the identification process in Israel was deeply flawed.
Miriam Radiwker, a respected lawyer assigned to the investigation, placed advertisements in Israeli newspapers identifying Demjanjuk and Federenko by name, and giving the alleged location of their crimes. She pasted their photographs next to each other at the bottom of a photo album page that also contained five other - markedly smaller - photographs. She showed the page to survivors she knew, many of whom were regularly in touch with each other. Nevertheless, it was stated at the Israeli trial that the identifications took place independently.
The main impact came from the testimony of the Treblinka survivors, and from Demjanjuk himself, whose falsification of almost every part of his wartime career made his one truth - that he was not the Treblinka Ivan - seem unbelievable.
On the last day of the Israeli trial, Demjanjuk's defence counsel, in a desperate gamble to avert his client's conviction, finally produced the Danilchenko statement. The judges accepted it in evidence, but incomprehensibly rejected a prosecution request for extra time to re-examine its implications. Six weeks later, in the most disturbing compromise of their 'guilty' verdict, the judges argued that Danilchenko's statement could be squared with Demjanjuk's life as Ivan the Terrible: he could have commuted between Treblinka and Sobibor. Flossenburg and Trieste, which nullified this theory, were ignored.
What is appalling is that the survivors were yet again dragged through a traumatic court case, and that the Israeli prosecutors and judges were forced to try a case on false premises.
The Demjanjuk case started in 1975, almost 18 years ago: a generation of Second World War veterans has died since then. How much will it take for us to realise that these war-crimes trials must now end?
It is an immensely difficult decision, for these men are guilty and it must go against the grain for anyone who knows what they did to see them go unpunished. Demjanjuk illustrates the dilemma well: even though we know now that he was not the monstrous Treblinka Ivan, it is beyond doubt that he must have been an SS auxiliary in the Sobibor death camp and the Flossenburg concentration camp.
The moral crux of this is that Demjanjuk is a guilty man; but not provably guilty of specific deeds - for there are no people left who can reliably testify about his actions. For the survivors of these hellish places, good and honest men and women though they doubtlessly are, too much time has passed, too much suffering has been endured, too many impressions are engraved in their minds and inevitably memories and nightmares, truth and hearsay have become blurred.
I hope the Israeli appeal judges, who have been deliberating on their final verdict since 10 June, will throw out this case. But I also hope they will ensure that Demjanjuk's acquittal on a flawed charge cannot be interpreted as a statement that he is an innocent man.
John Demjanjuk must be allowed to go home. The Nazi war-crimes cases must cease. The survivors must be allowed to rest. But every man who was guilty of foul deeds in that war, and in wars since, must be in no doubt, until the day he dies, that the whole world knows, and deplores, what was done.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies