Israel to investigate arrest, death of 'Prisoner X'

Jerusalem (CNN) -- An Australian-Israeli dual citizen who died in an Israeli prison gave Australian intelligence details of his work with Israel's Mossad before his arrest, an Australian television network reported Tuesday.

The fate of the man dubbed "Prisoner X" is now the subject of an investigation by Israel's parliament. Prime Minister Benjamin Netanyahu pleaded over the weekend for details to be kept quiet, warning "overexposure of security and intelligence activity" could harm Israel's security.

But the Australian Broadcasting Corporation has identified him as Ben Zygier, and it reported Tuesday that he had reported "every aspect of his work" for the Mossad, Israel's spy agency, to the Australian Security Intelligence Organization.

Zygier reportedly committed suicide in Israel's Ayalon Prison in December 2010, about 10 months after his arrest, according to ABC. His incarceration was a state secret, and Israel has never confirmed the prisoner's name or how he died.

ABC, citing unnamed sources, reported Tuesday that Zygier gave Australia "comprehensive detail about a number of Mossad operations, including plans for a top-secret mission in Italy that had been years in the making." Zygier helped Mossad set up a European communications company that sold electronics to Arab countries and Iran, according to the network.

The mystery of Israel's 'Prisoner X'

Who was Israel's 'Prisoner X'?

He met with Australian intelligence during a trip back to Australia, ABC reported. It wasn't clear who approached whom -- but ABC said it "believes" Zygier was arrested after Mossad discovered his contact with ASIO, fearing he had given up Israeli secrets.

A committee of Israel's Knesset announced Sunday that it would look into all aspects of the case, much of which remains under a gag order. Details about what happened to "Prisoner X" -- and why -- remain elusive.

'We are not like other countries,' Netanyahu says

In his weekly Cabinet address Sunday, Prime Minister Benjamin Netanyahu insisted Israel is committed to freedom of expression.

"However, the overexposure of security and intelligence activity could harm, sometimes severely, state security," he said.

"We are not like other countries," Netanyahu added. "We are an exemplary democracy and maintain the rights of those under investigation and individual rights no less than any other country. However, we are more threatened and face more challenges; therefore, we must maintain proper activity of our security agencies. And therefore, I ask all of you, let the security forces do their work quietly so that we can continue to live in security and tranquility in the state of Israel."

Israel's 'Prisoner X': Death of man with alleged spy agency ties

For two years, a government gag order prevented local journalists in Israel from telling the story. But after ABC brought the case to light last week, an Israeli court appeared to publicly confirm details about the case for the first time.

A statement from the court described a "prisoner who was both an Israeli citizen and a foreign national."

"The inmate was registered under a false identity for security reasons, but his family was notified immediately upon his arrest," the statement said. The court lifted part of the gag order, saying local media could quote foreign publications' reporting on the case -- but they could not do their own reporting on the story.

Criticism within Israel

Some Israeli lawmakers sharply criticized the government's handling of the matter.

"When unknown prisoners commit suicide and nobody knows who he is, how does that fit with a democracy with law which is proper?" Zahava Gal-On, leader of the Meretz Party, asked last week.

Pressed for answers by another lawmaker, Justice Minister Yaakov Neeman said that the matter should be investigated. But he said he could not answer the questions "because the subject is not under the jurisdiction of the Justice Ministry."

Dan Yakir, chief legal council for the Association for Civil Rights in Israel, sent a letter to Israel's attorney general about the case, criticizing the censorship and calling for the gag order to be scaled back further.

"What is far more concerning, of course, is the fact that a man was held in detention under heavy secrecy, and nothing was published about the reason for his arrest or the circumstances surrounding his death," Yakir wrote.

A culture of censorship

All journalists who apply for a government-issued Israeli Press Card must sign documents agreeing to the military censorship. According to the agreement, journalists will not publish security information that could benefit Israel's enemies or harm the state.

Breaking the rule could result in card revocation, and foreign journalists could lose their visas to work there.

In recent years, the censorship mechanism for checking scripts and pictures has rarely been practiced. Controls over content have faded more and more with the Internet as more freedom of information passes into the public domain.

Recent news of Prisoner X's case prompted Australian Foreign Minister Bob Carr to request an internal report.

"I'm advised in the form of an interim report that the Australian government was informed in February 2010, though intelligence channels, that the Israeli authorities had detained a dual Australian-Israeli citizen, and they provided the name of the citizen, in relation to serious offenses under Israeli national security legislation," Carr told a Senate committee Thursday.

He did not mention what the alleged "serious offenses" were.

Carr said Australia sought specific assurances from Israel, such as that the detainee would get legal representation of his choosing and that he would not be mistreated.

"At no stage during his detention did the Australian government receive any requests from the individual or his family to extend consular support," Carr said.

"The Australian government was advised through intelligence channels on December 16, 2010, (of) this individual's death on the previous day, and the deceased's family had been notified by Israeli authorities."

The Australian Embassy in Tel Aviv assisted in returning the body to Australia, Carr said.

Michael Schwartz reported from Jerusalem, and Holly Yan reported and wrote from Atlanta. CNN's Sara Sidner also contributed to this report.