Japan needs to revise its retrial system, which leads to prolonged proceedings that could last for decades, a sister of Iwao Hakamada, an aging former inmate on retrial for a 1966 quadruple murder in central Japan, said Wednesday.

"We have been fighting for 58 years, and finally we are in a retrial. This is ridiculously long," Hideko Hakamada, 91, told a press conference in Tokyo, ahead of a ruling slated for Sept. 26 for her 88-year-old brother, who is still facing a death sentence.

The start of the retrial in October last year at the Shizuoka District Court raised hopes that Iwao Hakamada would be acquitted, even though prosecutors again demanded the death penalty in the hearing, which concluded in late May.

Hideko appeared at the retrial in place of her brother who was exempted from attending due to his deteriorating mental state, having spent nearly half a century behind bars on death row before new evidence led to his release in 2014.

She said during the press conference that she was "unfazed" about the prosecutors sticking to their demand of capital punishment, saying they probably had no other way to respond.

While expecting the legal battle to "come to a close" with the retrial, she called for an amendment in the legal provisions for retrials for the sake of the many potentially wrongly convicted victims.

"I don't think Iwao should be the only one who should be saved," she said at the Foreign Correspondents' Club of Japan, along with a lawyer leading Iwao Hakamada's defense team.

Legal experts say the current retrial provisions, which are included in the criminal procedure law, make it increasingly difficult to swiftly start a new trial to re-examine matters from a concluded trial.

The criminal procedure law stipulates that a retrial will be opened if there is "clear evidence to find the accused not guilty." But it lacks provisions on the disclosure of information that is in possession of prosecutors and investigators for retrials, preventing easy access to evidence that could favor the convicted, experts say.

Prosecutors can also file an objection against a court decision to grant a retrial that may result in a higher court overturning the decision to reopen the case.

"We need the retrial law to be amended so that evidence favorable for the wrongly convicted will come out," Hideko said.

In Hakamada's case, it was only in 2010 that prosecutors, at the insistence of the court, disclosed evidence that helped fuel doubt on the death sentence finalized by the Supreme Court in 1980. This evidence included color photos of the five pieces of blood-stained clothing that he allegedly wore during the murder.

The Tokyo High Court, which was ordered by the top court in 2020 to re-examine its 2018 decision not to reopen the case, reversed course and ordered the retrial in March 2023, citing the unreliability of the main evidence -- the five pieces of clothing -- used.

The case marks the fifth time in postwar Japan that a retrial was granted for a crime in which the death penalty had been finalized. The four previous cases in the 1980s all resulted in acquittals.

Hakamata, a former professional boxer, was arrested in 1966 for allegedly murdering the senior managing director of the miso paste maker where he worked, his wife, as well as two of their children. They were found stabbed to death at their burned-down Shizuoka Prefecture home.

Though Hakamata initially confessed to the killings during intense interrogation, he pleaded not guilty at his trial, where he was indicted for murder, robbery and arson.