Israel’s Knesset will conduct an “intensive” investigation of why Melbourne native Ben Zygier was found hanged to death in his secret prison cell near Tel Aviv back in December 2010.

Israel has imposed a total media blackout on the case of the former Mossad employee turned prisoner, and held in such tight security that he was known only as “Prisoner X”.

The affair spilled out last week and has been a major embarrassment for the conservative Likud government and Mossad security agency.

Many questions are unanswered, not the least of which is how did a prisoner under constant surveillance manage to hang himself?  Australian officials are Israeli opposition lawmakers would like to know why Zygier was imprisoned, how he was tried, and what if anything he might have been doing for Mossad in Oz.