A new book claims an Israeli spy who committed suicide in prison was jailed for leaking secrets about a highly sensitive operation aimed at thwarting Iran while in an Australian university.

The book by Australian journalist Rafael Epstein, revealed Saturday in an excerpt published in the Sydney Morning Herald, contradicts earlier reports that Ben Zygier was put in an Israeli jail after an attempt to recruit a Hezbollah agent went awry.

Zygier, known until recently only as “Prisoner X,” hanged himself in 2010 under mysterious circumstances. His identity and reports surrounding his death came to light last year following an Australian investigative television report.

According to Epstein, Zygier revealed elements of an Israeli operation to an Iranian businessman at Monash University, where he was studying.

Zygier did not play a senior role in the operation, which involved an Italian telecom firm with ties in Africa and the Middle East, but was familiar with its workings.

“He had been to Tehran, and he knew plenty about what the Mossad was trying to do,” Epstein writes, according to a Haaretz report.

In May, Australian and German media reported that Zygier had been jailed after unwittingly exposing Israeli assets in Lebanon while on a maverick mission in a bid to regain good standing with his Mossad superiors.

According to a Der Spiegel report at the time, Zygier, who was apparently recruited by the Mossad spy agency in 2003, was sent to Europe in 2005 to infiltrate companies that were dealing directly with Iran.

Zygier’s mission was to try to gain access to potential informants in Iran and Syria. However, after two years, during which he was employed in the accounting division of a company, Zygier was recalled to Israel without having achieved substantial results.

Zygier, disappointed, was assigned a desk job but still hoped to find his way back into the field, Der Spiegel reported. Apparently acting on his own initiative, he began trying to recruit informants in Lebanon to spy on the Hezbollah terror organization. He contacted an affiliate of the group in a Balkan state and tried to recruit him. However, the Hezbollah activist succeeding in turning the tables and duped Zygier into providing information that eventually led to the arrest of a string of informants in Lebanon.

Meanwhile, after spending a year behind a desk, Zygier asked for permission to continue his academic studies in Melbourne, and in 2008 he began a graduate degree in Monash University. During the period of his studies, Zygier was apparently indiscreet about his activities with the Mossad, which eventually learned he was leaking details of his service, some of them inaccurate.

Zygier was called back to Israel to face an investigation during which details of his unauthorized solo Hezbollah operation came to light, according to the German report. He was subsequently arrested, incarcerated under strict secrecy, and charged with what one of his lawyers said were “serious” crimes.

However, according to Epstein, Zygier never embarked on the rogue mission to recruit Hezbollah operatives.

Epstein did not talk to Zygier’s family, who reportedly received a $1 million payout from Israel and have remained silent about the spy’s death.

However he claims in the book that Zygier attempted suicide several times before he took his own life in a heavily guarded cell on December 15, 2010.

According to Haaretz, Epstein and Zygier were involved in Zionist youth activities together.