Nazi war crimes: the hunt for Doctor Death

In September 1962, detectives arrived to arrest a wealthy gynaecologist in the West German spa resort of Baden-Baden. Unfortunately, the quality of their information was surpassed by that of their quarry. Aribert Heim, a man whose experiments in a Nazi concentration camp earned him the moniker of "Doctor Death" among inmates, had disappeared hours earlier.

The vanishing trick performed that day by Heim, then a respectable member of society in one of West Germany's most well-heeled cities and the owner of a property portfolio that included an apartment block in Berlin, was the beginning of a 46-year flight from justice for the world's most wanted Nazi war criminal. It has reputedly taken him through Egypt, Uruguay, Spain, Brazil, Argentina and Paraguay.

It is a fugitive's journey defined by the ability of Heim, who stands accused of the medicalised murder of hundreds of inmates in the most gruesome circumstances, to stay one step ahead of his pursuers. His repeated evasion of would-be captors including Mossad, the Israeli secret service, dates back to the end of the Second World War when he was inexplicably – and according to Nazi hunters "suspiciously" – released without charge by the American military.

It is also a saga that could be about to come to an end. Yesterday, two representatives of the Jerusalem office of the Simon Wiesenthal Centre, the body which has helped bring hundreds of Holocaust perpetrators to trial, stepped off a plane in southern Chile armed with information they believe could finally lead to the capture of a 94-year-old man with grey eyes and a distinctive duelling scar who stands accused of some of the most grotesque acts of cruelty in Hitler's Reich.

Efraim Zuroff, director of the centre in the Israeli capital, told The Independent that he had received "good information", understood to include a potential sighting, to indicate that Heim is alive and hiding in or around the Chilean city of Puerto Montt in the heart of Patagonia, where his daughter, Waltraud, 64, has lived for decades.

Mr Zuroff said: "There is information we have received which gives us good grounds for thinking that Heim is in Chile. We have received very good co-operation from Chilean and Argentinian authorities."

The arrival of Mr Zuroff and his Buenos Aires-based colleague Sergio Widder in Puerto Montt, a dramatically located port on the Pacific Ocean, is indicative of the urgency of capturing Heim and what the Wiesenthal Centre believes are hundreds of Holocaust criminals in their eighties or nineties who remain at large. In 2005, the organisation launched Operation Last Chance, a project to track down and arrest at least 300 suspects with the help of cash rewards and newspaper ads.

Heim, the son of an Austrian policeman who trained as a doctor in Vienna and joined the Nazi party three years before the Anschluss, remains the most cherished target of the Nazi hunters. Mr Zuroff, an American-born historian who succeeded Simon Wiesenthal as director of the centre, said last year: "We have expectations of catching all of them but if we only get Heim, it will be a success."

A reward of £250,000 for Heim's arrest is being offered jointly by the centre and the German and Austrian governments.

It is the barbarity in the name of medicine carried out by Heim, who served as a doctor in the Sachsenhausen, Buchenwald and Mauthausen camps after joining the Waffen SS, that has secured his position at the top of the list of surviving war criminals issued by Operation Last Chance.

He is accused of conducting his most gruesome experiments during his two-month stay in Mauthausen, close to the Austrian town of Linz, in 1941. Aided by an SS pharmacist, Erich Wasicky, he murdered hundreds of inmates by injecting various liquids, including gasoline, phenol, water and poison, into the hearts of prisoners to see which killed them the fastest. He used a stopwatch to time the results, recording them meticulously in a ledger.

Heim, whose experimentation was compared to that of the Auschwitz doctor Josef Mengele, also carried out amputations on prisoners without anaesthetic to see what level of pain a human could endure before expiring. Organs were removed from conscious patients, including one case where the liver, spleen and bowel were excised.

Mr Zuroff said: "His crimes are fully documented by himself because he kept a log of the operations that he carried out."

Testimony from captive orderlies who witnessed Heim's activities showed that he used body parts from his victims as decorations, once offering the camp commandant a present of seat coverings fashioned from human skin.

Karl Lotter, a political prisoner working at the Mauthausen clinic, described Heim's murder of an 18-year-old Jewish boy who came to have a swollen foot treated. After asking why he was so fit and being told it was because of playing football and swimming, Heim anaesthetised him. He castrated the boy, dissected a kidney and removed the second, then decapitated him. The head was boiled to remove the flesh so Heim could use the skull as a paperweight.

Mr Lotter said: "Of all the camp doctors in Mauthausen, Dr Heim was the most horrible."

After serving the rest of the war in Finland, Heim returned to Germany towards the end of the conflict and was arrested by the US military and questioned by war crimes investigators. His colleague, Wasicky, was tried and sentenced to death with other Mauthausen personnel in 1946 but Heim, whose conduct was known to his captors, was released in December 1947.

An indictment drawn up by German authorities in 1979 stated that Heim's US military file had been altered to remove any mention of Mauthausen, stating he was on a different SS attachment during the relevant dates. The indictment stated: "It is possible that through data-manipulation the short assignment ... to the concentration camp was concealed." Operation Last Chance described the decision not to prosecute Heim as "quite suspicious".

From 1947 until his flight into hiding in 1962, Heim was able to slip into a respectable existence, starting a family and setting up his gynaecology practice in Bad Nauheim, near Frankfurt, and then Baden-Baden, a little further south in the Black Forest. In 1958, he felt secure enough in his position to buy a 42-flat apartment block in Berlin and list it in his own name.

He had enough friends to ensure he was tipped off when the police moved in to arrest him four years later. It was the start of a long game of cat and mouse during which Heim is alleged to have worked as a doctor for the Egyptian police force and lived for many years on the Costa Brava.

Investigators have released pictures of their target, including a photofit to show him as he might look today and emphasising his V-shaped scar to the right of his mouth, reputedly suffered while duelling with swords.

As Heim followed the well-beaten path of fugitive Nazis to South America, investigators in Europe began to uncover clues that he was alive and well despite the insistence of his daughter that her father died in 1993 from cancer. His pursuers insist that money was sent, from an undiscovered Berlin bank account belonging to Heim and holding €1.2m (£900,000), to Spain and that the subsequent failure of his family to claim the money indicates he is alive.

Waltraud and her two half-brothers refuse to discuss him. German surveillance records showed that the mother of Heim's two sons phoned them to remind them of their father's birthday. Rüdiger Heim, one of the sons, who still lives in Baden-Baden, said: "All I can say is that it has been implied that I am in contact with my father, and that is absolutely false."

The lack of success has begun to reveal cracks in the once united front of his pursuers. German court officials last month rejected criticism from the Wiesenthal Centre which suggested they were delaying the hunt by refusing to grant a phone tap on the family.

As the focus switched to Patagonia yesterday, Mr Zuroff said: "The passage of time in no way diminishes the guilt of the perpetrators. Killers don't become righteous gentiles when they reach a certain age. And if we were to set a chronological limit on prosecutions, it would basically say you could get away with genocide."