This is the true story behind the intriguing but ultimately tragic story of Ben Zyiger: son, soldier, spy. Known only as Prisoner X, Zyiger was just 34 years old when he was found slumped in a small bathroom, separated from his cell by a transparent door. Locked behind bars in one of the most technologically sophisticated solitary jail cells in the world, it must not be easy to kill oneself, but Ben Zygier managed to do just that. Did he work for Mossad, the feared intelligence agency? Was he also working for ASIO? Was he a whistle blower or double agent, or simply a young man way out of his depth? In "Prisoner X," Rafael Epstein uncovers the intriguing story of a young Australian swept up in international espionage.