A 50-year old convicted sex attacker who completed a correctional course but then re-offended multiple times has returned to prison with a life sentence.

A lay-judge trial at the Osaka District Court on Thursday convicted Yasuhiro Nakanishi for 140 instances of rape and other assault on 20 females, including a junior high school student.

Nakanishi's earlier record of sex crimes saw him sentenced to eight years in prison. Upon release, and while still on probation, he went through Japan's correctional program for sex offenders.