Australian investigation: Guards didn't know of Prisoner X's identity

An investigation of Australian network ABC reveals that Ben Zygier, nicknamed Prisoner X, was held in complete isolation at a high-security cell build for the assassin of Prime Minister Yitzhak Rabin in the Ayalon Prison. It is unclear when he was arrested.

According to the investigation, Zygier's incarceration was so secret that not even guards knew his identity. (Ynet)