Facing retrial, exoneration and freedom after spending 15 years in prison for the 1997 murder of a Tokyo woman — a crime for which he was initially acquitted — Govinda Prasad Mainali could be a case study in the flaws in the nation's judicial system.

Like other foreigners in violation of their visa status, the Nepalese was placed in immigration detention after his acquittal, pending deportation. But prosecutors had other plans: They made sure he stayed in immigration custody as they retried his case on appeal, bent on a conviction.

To this end, they withheld evidence that would strongly establish reasonable doubt of guilt. In short, they presented, as a spokesman for the state said, what was needed "to prove their case."