They call him Prisoner X.

Media reports have described him as a man who hanged himself in an Israeli prison cell. But details about what happened to him and why have long been hard to come by.

The case, shrouded in mystery, sparked a government gag order that for two years stopped local journalists in Israel from telling his story, according to local media reports.

For years, Israeli government officials repeatedly declined to comment on the prisoner's death, which was first reported by the Ynetnews website in 2010.

Now, a new report about the man many in the media have dubbed "Prisoner X" -- because his name was never revealed -- is sparking widespread debate in Israel over government censorship and about the country's prison system.

According to an investigative report this week from the Australian Broadcasting Corporation, which did not disclose its sources, Prisoner X was a duel citizen of Australia and Israel and was recruited to join Israel's Mossad spy agency. The report identified him as Ben Zygier, alleging he was detained in 2010.

Details about why he was reportedly held in a high-security prison outside Tel Aviv, and what led to his death, remain unclear, according to the ABC report.

"The case is regarded as one of the most sensitive secrets of Israel's intelligence community, with the government going to extraordinary lengths to stifle media coverage and gag attempts by human rights organizations to expose the situation," ABC Foreign Correspondent Trevor Bormann wrote.

Several prominent Israeli media organizations wrote stories about the Australian report but then were asked to remove stories about it from their websites by government censors, according to Israel's Haaretz newspaper and an editor to which CNN spoke.

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.

Israeli lawmakers voice concerns

But word of the Australian report and subsequent Israeli government censorship quickly rang out in the halls of Israel's Knesset, with some lawmakers sharply criticizing the government's handling of the matter.

"We hear, in a state that is supposed to be a proper democracy, that journalists are cooperating with the authorities without the high court ruling that the case is a certain and imminent danger to the security of the state," said Israeli Parliament member Zahava Gal-On, leader of the Meretz Party. "When unknown prisoners commit suicide and nobody knows who he is, how does that fit with a democracy with law which is proper?"

During the Knesset session, another lawmaker asked Israel's justice minister about the case, point blank.

"Do you know about this? Can you verify the fact that an Australian citizen committed suicide in an Israeli prison under a made-up identity and the fact was not published that he was a prisoner in a prison in Israel?" asked Ahmed Tibi, a member of the Knesset.

Justice Minister Yaakov Neeman said that the matter should be investigated but that he could not answer the questions "because the subject is not under the jurisdiction of the Justice Ministry."

On Wednesday, a district court in central Israel lifted part of the gag order and ruled that local media could quote foreign publications' reporting on the case but also said they could not do their own reporting on the story.

Later that day, a statement from an Israeli court appeared to publicly confirm details about the case for the first time.

The statement, released by the court in the partial lifting of the gag order, 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 document also said that the prisoner was found dead in his cell two years ago and that a judge ordered an investigation into his death.

The death was recently ruled a suicide, the statement said, and authorities are investigating whether there was negligence in the case.