For someone who enjoys the awesome reputation as the world's last Nazi hunter, Efraim Zuroff is disarmingly candid about how he started in the business of tracking down the perpetrators of genocide. Born in 1948, he had neither direct experience of the Holocaust nor any burning teenage ambition to bring mass murderers to justice. In fact he was more interested in basketball.
"As a youth growing up in New York, my sole ambition was to become the first orthodox Jew to play in the NBA – the National Basketball Association," he admits.
But all that changed in the early summer of 1967, when the man who now heads the Jerusalem office of the Simon Wiesenthal Centre was 18 and Israel was on the brink of war.
The young Efraim Zuroff was sitting at home with a copy of The New York Times looking at a map and graphics of the Middle East. They showed an Israel surrounded and hopelessly outnumbered by hostile Arab neighbours. Mr Zuroff recalls: "My instinctive reaction was, there's going to be another Holocaust, even though I hardly knew what the Holocaust was really about, apart from that it had happened."
The Six Day War brought the issue of Jewish identity and the Holocaust into sudden and sharp focus for Mr Zuroff, and he went to study the subject at New York's Yeshiva University and the University of Jerusalem. He moved to Israel, joined the Simon Wiesenthal Centre, and has since published numerous books on the subject and established himself as a world authority on Nazi genocide.
Yet the next few days are likely to be both a high point of Mr Zuroff's career and the beginning of the end of the road for the hunters of Hitler's Nazis. As a direct result of his efforts, the two men rated as the world's most wanted Nazi war crimes suspects are facing justice.
Last week Mr Zuroff was in Budapest to attend the opening of the trial of 97-year-old Sandor Kepiro, a former Hungarian police captain who is accused of massacring more than 1,200 Jewish, Serbian and Roma civilians in the Serbian town of Novi Sad in 1942. Mr Zuroff tracked down Mr Kepiro in 2006. He says his court appearance "may be the last Nazi trial in eastern Europe".
On Thursday, a court in Munich is set to deliver a verdict on 91-year-old Ukrainian-born John Demjanjuk, the world's other "most wanted" Nazi war crimes suspect. Mr Demjanjuk, a former guard at the Sobibor Nazi death camp, is charged with complicity in the murder of 27,900 predominantly Dutch Jews. He is alleged to have been one of the guards who literally drove Holocaust victims into the gas chambers with whips.
Mr Zuroff admits that suspected war criminals like Mr Demjanjuk were simply the cogs in the Nazis' genocidal machine. "He may not have been Heinrich Himmler, but he made the system work. Without these people the Holocaust would never have taken on the dimensions that it did," he insists.
Under Mr Zuroff's direction, the Simon Wiesenthal Centre launched its "Operation Last Chance" in 2002 in an attempt to bring the last surviving Nazi war criminals to justice. The campaign produced results. The names of more than 100 suspects have been handed to prosecutors and over the past decade there have been 89 court rulings against Nazi war criminals. Last year there were 852 investigations being conducted against Nazi war crimes suspects worldwide.
Yet part of the success of Operation Last Chance – which is also the title of Mr Zuroff's book on the subject – has been put down to a sea change in the German judiciary's attitude to war criminals. German prosecutors have switched from being reluctant to willing in their pursuit of Hitler's henchmen. The Demjanjuk case is a prime example.
"Nowadays, the Germans realise that it is to their credit to prosecute such people," Mr Zuroff says. And while in the immediate aftermath of the Second World War there were thousands of suspects at large, now only a handful remain alive.
"In other words the amount left in the queue make it doable," is how Mr Zuroff puts it.
The same cannot be said of Austria, the country of Hitler's birth, which Mr Zuroff accuses of having a deplorable record on the prosecution of its Nazi criminals.
"They have not convicted one of these people in more than 30 years and this is absolutely outrageous," Mr Zuroff says. He cites the case of Erna Wallisch, a former Austrian death camp guard who was exposed in 2006 as having admitted taking Jewish inmates to the gas chambers. A request that she be prosecuted was turned down by the then Austrian justice minister on the grounds that Wallisch was merely guilty of "passive complicity in genocide" and therefore could not be prosecuted under Austrian law.
"I just could not believe it," Mr Zuroff exclaims. "I put their reluctance down to sheer lack of political will and the kind of thinking that makes some Austrians think they were Hitler's first victims," he adds.
Despite the Simon Wiesenthal Centre's recent successes, there was probably always going to be the "big fish" who got away. For Mr Zuroff, it was Aribert Heim, the Nazi "Doctor Death" who conducted hideous experiments – including removing victims' kidneys without anaesthetic – on inmates at the Mauthausen concentration camp in Austria.
Heim, who briefly worked undetected as a doctor in post-war West Germany, eventually fled abroad. There were numerous alleged sightings of him in various countries and in 2008, Mr Zuroff went to South America, convinced that he would be captured within weeks. But he was never caught, and months later a New York Times investigation claimed that Heim died in Cairo in 1992, having lived there for years.
"In some ways Heim was my biggest failure," Mr Zuroff says. Yet in the light of fresh revelations this year about the extent to which the CIA and West German intelligence co-operated with Nazi criminals after the war, Mr Zuroff thinks it quite possible that Heim worked for West German intelligence. "I have no concrete evidence, but I think it's a safe bet and the reason why he was never prosecuted," he says.
Heim is now almost certainly dead, and Alois Brunner, the other top Nazi still unaccounted for, is also presumed dead in Syria. But Mr Zuroff says there are still hundreds – possibly thousands – of minor Nazi war criminals still at large. The majority will probably never be brought to justice.
"Time is running out and it's now or never. Basically we have run into injury time," Mr Zuroff says.
So is the world's last Nazi hunter about to become a redundant fighter without a cause? Efraim Zuroff does not think so.
His main concern right now is eastern Europe, which, with the exception of Poland, he sees as being engaged in a post-Cold War drive to re-write history and gloss over its involvement in the Holocaust. He says an important part of this process is the attempt by many new eastern European countries to equate Nazi genocide with Soviet oppression.
"The argument goes like this," Mr Zuroff says. "If communism equals Nazism then communists committed genocide, so Jews, many of whom were communists, also committed genocide. If Jews committed genocide, then what are you bothering us about with our murders? If everyone is guilty, no one is guilty."
Mr Zuroff says his current task is to find the right language to combat the arguments of those east Europeans who want to re-write history to escape blame for their countries' complicity in the Holocaust.
The three Baltic states – especially Latvia's SS-veteran supporting Fatherland and Freedom party, which is an ally of the British Conservatives in the European Parliament – are prime culprits, he maintains.
"This will keep me busy for the next decade," Mr Zuroff says. He jokes that there is a "mystical reason" for his self-imposed mission to go on trying to tell the truth about the Holocaust. "After all, my name is Efraim, and my grandfather chose it as it belonged to somebody who was murdered along with his whole family in the death camps. The original Efraim was a good Talmud scholar – unlike me," he adds.
Brought to ground
1999: Dinko Sakic
Zuroff played a key role in the arrest of Sakic, a Croatian former commander of the Jasenovac concentration camp. Sakic was extradited from Argentina and sentenced in Zageb to 20 years imprisonment in 1999. He died in 2008.
2006: Sandor Kepiro
Zuroff exposed the suspected Hungarian Nazi war criminal Kepiro, who went on trial in Budapest last week charged with the murder of more than 1,200 Jewish, Serb and Roma civilians in a massacre in the Serbian town of Novi Sad in 1942.
2008: Charles Zentai
Zuroff helped to track down Zentai, another suspected Hungarian Nazi, who is accused of murdering an 18-year-old Jew during the Second World War. Zentai is currently fighting extradition to Hungary from Australia.