Israel has confirmed it jailed a foreigner in solitary confinement on security grounds who later committed suicide, as Australia admitted Thursday it knew one of its citizens had been secretly held.

The man, identified by Australian media as Mossad agent Ben Zygier, known as “Prisoner X”, died in a secret prison near Tel Aviv in 2010 in a case Israel went to extreme lengths to cover up, imposing media gag orders.

Tel Aviv broke its silence after the Australian Broadcasting Corporation said the man was a dual Australian-Israeli citizen and reported that he was a spy for Israel’s intelligence agency.