One of the many mysteries surrounding the tale of Israel's "Prisoner X"—an alleged Mossad spy who killed himself after arrested by his own people—is one of the simplest: Why was he in jail in the first place? A continuing investigation by determined media outlets seems to show that the prisoner's real crime was that he wasn't very good at his job.

If you're just catching up to the story, last month "Prisoner X" was revealed to be Ben Zygier, and Australian-born Jewish man who immigrated to Israel and was recruited to join its highly secretive intelligence service. (Reportedly because his Australian birth and passport made it easy for him escape notice in other countries.) In 2010, however, he was just an anonymous prisoner who had somehow killed himself in an Israeli jail, sparking inquires from local authorities, though no one would say who he was and why he was arrested.

After an Australian news program broke the story of Zygier's identity earlier this year, more questions were raised about why the Israelis would arrest someone who was supposedly on their side. Now a new report by Australia's Fairfax newspapers and Germany's Der Spiegel magazine seems to fill in some of the details.

According to their stories published this weekend, Zygier was trained to be a corporate mole, infiltrating companies that had connections to Israeli enemies like Iran and Syria. But he apparently wasn't doing a very good job ("neither particularly bad nor particularly good, but mediocre") and was reassigned to desk duty in Tel Aviv. Desperate to prove his worth, Zygier took it upon himself to try and recruit new double agents. Unfortunately, he chose a man with close ties to the Lebanese terrorist group Hezbollah and in effort to impress him/prove he was legit, Zygier allegedly gave the man the names of Israel's top two Hezbollah informants, getting both of those men arrested in Lebanon.

That spectacular failure alone should have been enough to get Zygier drummed out of the service, but when he was actually arrested in 2010, he was allegedly carrying even more information that he may have been planning to pass along to his Lebanese contacts.

So given the circumstances (and assuming these new reports are true) Zygier's arrest and his placement in a high security Israeli prison starts to makes sense. What happened after that, however, is still the source of a lot of important questions that have yet to be answered: How was he being treated? What was his mental state? Was he ever going to face trial? And most important of all—how did a man in a closely monitored, "suicide-proof" cell manage to hang himself?

In the end, it's a sad story of a man who wanted nothing more than to help his adopted country, but seems to have only made things worse for everyone. It remains to be seen if anyone else will answer for it.