A Knesset panel will launch an independent investigation into the jailing and suicide of Mossad agent Ben Zygier, following growing calls for an official accounting of the case, the committee said Sunday night.

The Knesset Intelligence Subcommittee, a section of the Foreign Affairs and Defense Committee, will probe what led Zygier, a Melbourne native, to be jailed and then to commit suicide in a high-security jail cell in Ramle in 2010.

An Israeli security official said Sunday that Zygier was offered a plea bargain that would have seen him serve less than 10 years in prison, but that the accused spy decided to take his own life “out of shame.”

According to the official, quoted by Israel’s Channel 2 news, Zygier was offered the deal in return for his assistance in the investigation.

“No one ‘hunted’ Zygier down,” the security official told Channel 2, apparently relating to hinted allegations that the Mossad was behind Zygier’s death. “He died of shame. We agreed that the courts send him to a single-digit prison term, provided that he help in the investigation, repair damages and commit to ‘shut up.’ ”

It is still not clear what crimes Zygier was accused of committing, and many facts of the case remain under wraps. The announcement of the Knesset probe came hours after several MKs called for an independent inquiry into the case.

Channel 2 reported Sunday that Zygier’s lawyers negotiated for the possibility of signing a plea agreement and that outlines for such an agreement had been reached in the days before the agent put an end to his life.

Top defense lawyer Avigdor Feldman, who met with Zygier at the jail shortly before his death, said Zygier was uncertain about taking the plea bargain, and had been told he faced a very lengthy jail term for “serious” crimes if he did take the deal, and a still longer term if he went through with the trial and was convicted. Zygier, a 34-year-old married father-of-two, had also been told he would be ostracized by his family, Feldman said.

The case of Zygier — until recently known only as “Prisoner X” — has ignited a firestorm in Israel and Australia, with politicians and the media on both sides of the ocean demanding an accounting of why the Mossad spy was jailed; and how and why he killed himself while under heavy surveillance in his Ramle jail cell.

Australian Foreign Minister Bob Carr announced on Sunday that his country would launch a formal investigation into the circumstances surrounding Zygier’s death.

“We have asked the Israeli government for a contribution to that report,” Carr said. “We want to give them an opportunity to submit to us an explanation of how this tragic death came about.”

Moshe Cohen, a spokesman for Israel’s Justice Ministry, said the ministry would consider this week whether to publish the coroner’s report that ruled the prisoner had committed suicide. It will also consider publishing details of a separate probe into possible neglect in the guarding of the prisoner, he said.

“After this case exploded, there was public interest,” Cohen said. “Whatever isn’t secret we need to publish.”

It has been widely reported that Zygier was recruited by the Mossad after immigrating to Israel in 2000; was questioned by the Australian security authorities back in his country of birth nine years later; was arrested in Israel in early 2010; and committed suicide in his cell in Ramle’s Ayalon Prison on December 15, 2010, aged 34.

There were no cameras in the bathroom, which explained the lack of video evidence for the suicide, despite the fact that Zygier was reportedly under suicide watch and held in a high-tech cell under 24-hour surveillance, according to a report on Channel 2.

Speaking to the Cabinet Sunday morning, Prime Minister Benjamin Netanyahu warned against overexposure of the affair, which could harm Israel’s security interests.

However, Jewish Home MK Uri Ariel sent a letter on Sunday to acting Speaker of the Knesset MK Binyamin Ben-Eliezer and to Zeev Elkin, the chairman of the Knesset Steering Committee, demanding they take steps to enable an investigatory committee to look into Zygier’s case. Ariel asked that the Steering Committee appoint a temporary chairman for the Knesset State Comptroller Committee — currently not in session — which would then enable that body to meet and establish a probe.

On Saturday, MK Eitan Cabel (Labor) called for an independent and nonpartisan investigation into the incident, saying he ceased looking into the matter two years ago at the request of intelligence officials.

“I don’t have the slightest shadow of a doubt that it needs to be investigated and checked by an external and independent body,” he said. “It is absolutely wrong for there to be a consensus supporting such grave actions by the defense establishment, to the extent of making people vanish.

“The current episode should lead to a shake-up in all the branches of the security establishment,” continued Cabel. “When it comes to anything to do with media [the attempt to suppress coverage] shows conservatism or ignorance or both. Perhaps our boys haven’t noticed, but the world has changed.”

Cabel said that he first became aware of “Prisoner X” after reading a report on a news website in 2010 and began to look into the case, but encountered pressure from “the highest ranks of the intelligence community,” who convinced him to abandon his requests for information.

The chairman of the Knesset Foreign Affairs and Defense committee at the time, MK Tzachi Hanegbi (Likud), said that he received no official information about Zygier during the period either.

In an interview with Israel Radio on Sunday, Hanegbi said the matter required investigation. But he hastened to add that, despite the mysterious circumstances of Zygier’s arrest, he was sure it was not “totalitarian state-style.”