A suspected Mossad agent known as Prisoner X was arrested by his own spymasters after leaking detailed information about his work to Australian intelligence services, according to sources cited by broadcaster ABC Monday.
Ben Zygier, an Australian-Israeli, gave Australian intelligence officials a comprehensive account of a number of Mossad operations, the sources told the Australian Broadcasting Corporation.
Israel's parliament said it would launch an "intensive" inquiry into Zygier's arrest and death after the ABC's Foreign Correspondent programme last week exposed his identity.
According to the ABC, Zygier was found hanged in his cell in Ayalon prison near Tel Aviv in December 2010, in a case Israel went to extreme lengths to cover up.
It imposed a total media blackout on the case but was forced to ease the restrictions after the story made headlines across the world, rendering the local gag order ineffective.
Prime Minister Benjamin Netanyahu said Sunday that shining too much light on intelligence activities can "badly damage" state security.
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ABC said sources have told the Foreign Correspondent programme that Zygier gave Australian Security Intelligence Organisation (ASIO) officials information that included plans for a top-secret mission in Italy that had been years in the making.
It is unknown who initiated the contact with the Australian intelligence services, which came during one of his frequent visits back with his wife and children.
In one of four trips to Australia in the years before his death he reportedly applied for a work visa to Italy.
ABC said it understood Zygier was one of three Australian Jews working for Mossad who changed their names several times, taking out new passports as they travelled in the Middle East and Europe.
Zygier reportedly set up a Europe-based communications company for Mossad that exported electronic components to Arab countries as well as Iran, a venture that employed the two other dual citizens.
Zygier, who immigrated to Israel in around 2001, is believed to have been arrested in February 2010. He was found hanged in his cell 10 months later despite being under 24-hour surveillance.