Hakamada, a former professional boxer, was working at a miso processing plant in 1966 when the bodies of his employer, his wife and two children were found in a fire at their home in Shizuoka, west of Tokyo. All four had been stabbed to death.
Authorities accused Hakamada of killing his family, setting fire to their home and stealing 200,000 yen in cash.
Hakamada initially denied robbing and killing his victims, but later described being beaten and interrogated for up to 12 hours a day, forcing him into making confessions.
In 1968 he was convicted of murder and arson and sentenced to death.
