Simon Wiesenthal, the Holocaust survivor who dedicated his life to tracking down Nazi war criminals, was seen all his life as a one-man organization. But now, documents from his estate show he was a Mossad agent.

A new book by Tom Segev, to be published on Thursday, reveals that the Mossad supported Wiesenthal - and also shows that Israel did more to capture Nazi war criminals than was previously known.

The book, "Wiesenthal - the Biography" (published by Keter ), reveals that a 1948 Israeli operation to capture Adolf Eichmann in Austria failed.

Wiesenthal, whose efforts to trace war criminals and bring them to justice won him world acclaim, died five years ago in his Vienna home, aged 97.

During the Holocaust, he was a prisoner in five concentration camps. After the war he contacted American intelligence services and provided them with Nazi criminals' names. He was also active in the underground organization Bricha ("escape" ), which helped Jewish Holocaust survivors flee Europe for Palestine.

When Israel was established, Wiesenthal was enlisted to work with the Mossad's predecessor, the Foreign Ministry's "state department." Though he was not Israeli, he received an Israeli passport that enabled him to remain in Austria.

In December 1948, the department sent three agents, headed by Israel Defense Forces officer Michael Bloch, to Austria. With Wiesenthal's help and the Austrian security services' cooperation, the agents lay in wait for Eichmann in the Alpine village of Altaussee, where Eichmann's wife lived with her children. They believed Eichmann, who had escaped from the American POW camp Oberdachstetten, would visit his family for the new year.

But Eichmann never showed up. Perhaps he had been warned at the last moment of the Israelis' presence in the village.

Bloch wrote a detailed report of the operation that was only recently released for publication. Asher Ben Natan, a senior "state department" official who later became Israel's ambassador in Germany and France, confirmed the story.

In 1953, Wiesenthal located Eichmann and reported his whereabouts to the Israeli authorities. But only in 1960, following intelligence from Germany, did Israeli agents set out to capture him.

Wiesenthal started working for the Mossad after Eichmann's capture and continued doing so for about 10 years. His main job was to trace Nazi criminals, but he also provided his operators with information about German missile scientists and engineers working in Egypt.

The Mossad financed the establishment of Wiesenthal's office in Vienna and paid him some $300 a month in cash as wages.