Tokyo, Oct 5 (IANS): An 89-year-old Japanese death-row inmate convicted of fatally poisoning five people in 1961 has died while seeking a retrial, the media reported.

Justice ministry officials said Masaru Okunishi died of pneumonia in a medical prison in a Tokyo suburb on Sunday. He was transferred from the Nagoya prison in 2012 after his health deteriorated.

His defence lawyers had filed a ninth petition for a retrial in May.

Okunishi was sentenced to death for killing five women with pesticide-laced wine at a community gathering in Nabari, Mie prefecture, in 1961.

A district court initially found him not guilty, but a high court reversed the ruling. His death sentence was finalised by the Supreme Court in 1972.

Okunishi consistently declared his innocence at his trial and repeatedly sought a retrial.

In 2005, the Nagoya High Court granted a retrial, saying he could not be convicted as the perpetrator.

A judge in a different section of the same court annulled the decision the next year. But the Supreme Court overturned the decision and ordered the court to decide again whether to retry him.

The top court in 2013 finalised a decision not to open a retrial.