WASHINGTON -- Simon Wiesenthal, the controversial Nazi hunter who pursued hundreds of war criminals after World War II and who was central to preserving the memory of the Holocaust for more than half a century, died yesterday at his home in Vienna, the city that was his base of operations. He had a kidney ailment and was 96.
Called the ''deputy for the dead" and ''avenging archangel" of the Holocaust, Mr. Wiesenthal after the war created a repository of concentration camp testimonials and dossiers on Nazis at his Jewish Documentation Center. The information was used to help lawyers prosecute those responsible for some of the 20th century's most abominable crimes.
Mr. Wiesenthal spoke of the horrors first-hand, having spent the war hovering near death in a series of labor and extermination camps. Nearly 90 members of his family perished.
After the Nuremberg Trials of the late 1940s, Mr. Wiesenthal remained a persistent and lonely voice calling for war crimes trials of former Nazis. This was later considered by many a remarkable achievement during the Cold War, when the major world powers were recruiting former Nazis to help govern countries along the Iron Curtain. There was little political will to relive World War II, and few cared to challenge that perspective.
Martin Mendelsohn, a Washington lawyer who in the late 1970s helped establish the Nazi-hunting Office of Special Investigations within the US Justice Department, said in an interview that Mr. Wiesenthal ''kept the memory of the Holocaust alive when everyone wanted it to go away. When Jewish groups wanted it to go away, he wanted to keep it alive. That is his signal accomplishment."
Following the principle ''justice, not vengeance," Mr. Wiesenthal said trials of Nazis would provide moral restitution for the Jews and would have the best chance of preventing a recurrence of the anti-Semitism that defined the first half of his life.
''I'm doing this because I have to do it," he once said. ''I am not motivated by a sense of revenge. Perhaps I was for a short time in the very beginning. . . . Even before I had had time to really think things through, I realized we must not forget. If all of us forgot, the same thing might happen again, in 20 or 50 or 100 years."
That mission continues to drive wide-ranging efforts of the Simon Wiesenthal Center, which has offices on four continents and educational programs at the New York Tolerance Center and the Museum of Tolerance in Los Angeles, said Mark Weitzman, director of the center's Task Force Against Hate and Terrorism in New York.
A former prosecutor in Boston praised the center yesterday for its efforts in spurring the Lithuanian government to action after Aleksandras Lileikis fled there from Boston in 1996. Lileikis had lived in Boston for decades, concealing his past as director of security police in Vilnius in World War II.
Lileikis was stripped of his citizenship after a trial in US District Court in Boston but fled before he could be deported.
David S. Mackey, who prosecuted Lileikis through the Office of Special Investigations, said the Wiesenthal center had pressured the Lithuanian government to prosecute him, which it did.
''That was a heroic thing to do," Mackey said. ''The Wiesenthal center made an extraordinary effort to force the Lithuanian government to take criminal action against the war criminal in their midst."
Lileikis died awaiting trial in 2000.
Weitzman said that Mr. Wiesenthal taught that justice was not measured only by court convictions.
''Simon pointed out many times that one of his goals was to keep the pressure on Nazi war criminals even 40, 50, 60 years after their actions," Weitzman said. ''It was to remind people ready to commit genocide today that they will not find a safe haven, that they will not be able to rest easy."
Mr. Wiesenthal's targets included Adolf Eichmann, one of the foremost planners of Jewish extermination; Fritz Stangl, commandant of the death camps Treblinka and Sobibor; Gestapo officer Karl Silberbauer, who arrested Anne Frank in her Amsterdam hideout; and Hermine Braunsteiner Ryan, who helped process the murder of women and children at a camp in Poland and who later was found living as a housewife in Queens, N.Y.
Through informants, who included veterans of rival Nazi-era intelligence services, Mr. Wiesenthal helped expose such organizations as Odessa, which slipped former Nazis to South America. In various ways, including procuring prosecution witnesses, Mr. Wiesenthal said he helped bring 1,100 former Nazis to trial.
His most celebrated early case concerned Eichmann, who had vanished after the war. To Mr. Wiesenthal, Eichmann was the essence of the ''desk murderer," the bureaucrat whose policies condemned to torture or death tens of thousands at a time.
In 1947, Eichmann's wife sought to have the Nazi official declared dead. Mr. Wiesenthal was able to prove the alleged witness to the death was Eichmann's brother-in-law, preventing the death certificate from being approved.
By keeping the file active, he helped launch an international manhunt that resulted in Eichmann's capture by Israeli intelligence. In 1960, Mossad agents kidnapped Eichmann from a street in Buenos Aires. He stood trial in Israel and he was hanged in 1962.
An early book by Mr. Wiesenthal, ''I Hunted Eichmann" (1961), had a more boastful title than the content inside suggested but made its author an overnight sensation after years of toiling in obscurity, according to biographer Hella Pick.
Because of Mossad secrecy over the kidnapping, Mr. Wiesenthal's role appeared magnified, and he took advantage of the publicity to press his cause. This led to later denunciations of Mr. Wiesenthal by a former Mossad leader -- one of many enemies Mr. Wiesenthal made among leading Jewish figures who criticized his methods -- but the Nazi hunter was unapologetic.
''Through the publicity, we got information, and through the publicity, we got money," Mr. Wiesenthal once said, noting that the money was essential sometimes to persuading aging Nazis to talk.
He embraced more romantic, sometimes fictionalized depictions of his work, as was the case in Frederick Forsyth's novel ''The Odessa File" (1972).
Mr. Wiesenthal was born Dec. 31, 1908, in the Galician town of Buczacz, part of what is now the western Ukraine. His father, a sugar wholesaler, died while fighting in World War I, and the family struggled amid competing Ukrainian, Russian, and Polish forces.
It was common to find drunken soldiers raping and killing Galicians, especially Jews. When his mother sent him one day across the street to a neighbor's house to borrow yeast, a saber-wielding Cossack slashed Mr. Wiesenthal's right thigh. The scar remained for the rest of his life.
After attending Czech Technical University in Prague, Mr. Wiesenthal formed a small architectural practice in the Ukrainian city of Lvov. In 1936, he married Cyla Mueller, his girlfriend since high school.
Their few prosperous years ended with the dissolution of the Soviet-German ''non-aggression" pact of 1939. Stalin unleashed his security apparatus on the Ukraine. Forced from his livelihood, Mr. Wiesenthal worked as a mechanic in a bedspring factory and unsuccessfully tried to bribe security officials from taking away his family to certain death.
Mr. Wiesenthal himself was rounded up with other Jews and nearly murdered by Ukrainian soldiers. Each man stood against a wall and beside a wooden crate that was meant to hold a corpse. An officer shot a man in the neck, swigged liquor, and shot the next man. As the officer approached Mr. Wiesenthal, church bells sounded. ''Enough!" the officer said. ''Evening Mass!"
''What I saw for the first time was systematic extermination that had no motive except to kill every Jew, starting with the ones who looked the most dangerous to Hitler. And done by people who took real pleasure in killing us," he told his biographer Alan Levy.
Mr. Wiesenthal and his wife were forced to work in a labor camp. He helped Cyla, a blonde who could pass as Polish, escape through the underground, but each thought the other died during the war.
They found each other months after the German surrender by scanning lists of survivors. She remained, until her death in 2003, Mr. Wiesenthal's solid, if long-suffering, defender. Mr. Wiesenthal could never stop his work and once turned down her suggestion that they move to Israel and ''be normal people."
Survivors include their daughter, Pauline, of Herzliya, Israel, and three grandchildren.
During the war, Mr. Wiesenthal grew to think survival was unlikely and twice attempted suicide. He said the turning point was a conversation with an SS corporal one day toward the end of the war. The man bet Mr. Wiesenthal that no one would ever believe the truth of what had occurred in the concentration camps.
Their exchange, Mr. Wiesenthal later said, brought him the will to live through the war.
By May 1945, when Mr. Wiesenthal was freed by Allied soldiers at Mauthausen camp in Austria, his 6-foot-tall body weighed 99 pounds. Gradually restored to health, he transferred to an Allied base in Linz, Austria. To combat his malaise, he went to the war crimes office and offered his services after presenting an exhaustive list of crimes he had witnessed.
He chose to remain in Austria because he held many of its citizens culpable for the deaths of millions of Jews. He worked with a Jewish relief agency to clear names of suspected Nazis and, in what became known as ''Lex Wiesenthal," demanded that Jewish collaborators have no place in postwar Jewish organizations.
In 1947, he started his independent Jewish Documentation Center in Linz (later it was based in Vienna).
When money ran out in 1954 -- his chief benefactor, a Swiss Jew, had died -- he closed his center and worked for a Jewish vocational training organization. Mr. Wiesenthal returned to chasing war criminals full time only with publicity from the Eichmann case.
He often spoke of the necessity of his work by citing the Anne Frank case and his search for the man who arrested her family. He started the hunt after meeting a postwar generation of Austrians who labeled the horror stories of death camps ''Jewish propaganda" and viewed ''The Diary of Anne Frank" as a hoax.
Through contacts and resources such as the telephone directory of the Gestapo in Holland, he found Frank's arrestor, Silberbauer, working as an inspector for the Vienna police. When the man was suspended in 1963, Mr. Wiesenthal phoned the Dutch press.
But the case went nowhere when prosecutors said Silberbauer's actions were not war crimes and he was not responsible for Frank's deportation to a concentration camp. Mr. Wiesenthal grew more convinced of the need for a rigorous press offensive in the future.
He did just that in the 1960s and 1970s during his successful campaign to prevent the expiration of German statutes of limitation against Nazi war criminals. He enlisted the help of Senator Robert Kennedy, one of his chief American admirers.
To many, his name was a symbol of human conscience. Mr. Wiesenthal's honors included the US Congressional Gold Medal (1980), the Presidential Medal of Freedom (2000), and an honorary British knighthood (2004).
In 1977, Rabbi Marvin Hier named his Los Angeles-based Jewish human rights center after Mr. Wiesenthal. Mr. Wiesenthal remained officially unaffiliated with the center, but Hier agreed to send him a modest monthly stipend as he kept his office open, mostly hoping to outlive the surviving handful of his prey.
Mr. Wiesenthal wrote prolifically to provide some income for his center. Besides his memoirs, his books included ''The Sunflower" (1969), part-memoir, part-parable of forgiveness; and ''Sails of Hope" (1973), in which he studied the possibility that Christopher Columbus was Jewish.
Mr. Wiesenthal will be buried in Israel.
''Simon Wiesenthal acted to bring justice to those who had escaped justice," Israeli Foreign Ministry spokesman Mark Regev told Reuters yesterday. ''In doing so, he was the voice of 6 million."
Ever image-conscious, Mr. Wiesenthal once said Paul Newman would be the ideal man to play him onscreen. When told the actor disliked portraying the living, Mr. Wiesenthal said: ''Give him also my regards, but for his comfort I wish not to die."
Judy Rakowsky of the Globe staff contributed to this report.