Lawyers seeking a retrial for a former professional boxer on death row for 42 years filed their final statement Tuesday with the Supreme Court, demanding that the court "have the courage to acknowledge its misjudgment" and free their client.

Iwao Hakamada, 71, has demanded a retrial after he was convicted of murdering a family of four in 1966. His death sentence was finalized in 1980 by the Supreme Court, but a retrial plea has continued since 1981.

"The court has imprisoned a man and will execute him, despite the unreasonable, unnatural and questionable facts in the rulings," the final statement by his lawyers said. "Such a reckless act cannot be accepted."

Katsuhiko Nishijima, who heads Hakamada's defense, said a decision by the Supreme Court regarding the retrial plea could "come any minute."

He said that chief evidence, including the weapon allegedly used in the slayings, was "fabricated" to convict the former featherweight boxer.

Hakamada was convicted by lower courts of murdering a miso maker, his wife and two children in Shizuoka Prefecture on June 30, 1966. The scene of the crime was torched and ¥200,000 was stolen.

Hakamada was arrested the following August. The former boxer, who was a live-in employee of the miso factory, resided next door to the victims' house. He was charged with murder, robbery and arson, and was sentenced to hang by the Shizuoka District Court. The Tokyo High Court upheld the sentence as did the Supreme Court.

However, Nishijima and his team claim that coercive questioning, including beatings by interrogators, led to Hakamada's initial confession. They also argue that evidence provided by police lacks credibility.

Bloodstained garments found at the miso plant by police in August 1967, more than a year after the killings, were too small to fit Hakamada, the lawyers said.