Unless public prosecutor's offices are forced to submit to outside oversight, more travesties of justice like the one allegedly committed by prosecutor Tsunehiko Maeda will discredit the Japanese legal system, experts say.

People familiar with public prosecutor's offices say they are infected with systemic problems that foster an environment in which suspects are forced into confessing to scenarios made up by the prosecutors themselves.

This is what happened to Atsuko Muraki, the senior welfare official who was apparently falsely indicted by the Osaka District Public Prosecutor's Office in a high-profile case that unraveled last month.