[4] In March 2014, he was granted a retrial and an immediate release when the Shizuoka District Court found there was reason to believe evidence against him had been falsified.

According to Hakamada, he helped extinguish the fire only to find the bodies of the executive, his wife, and two children, all stabbed to death.

[10] Hakamada was interrogated and, in August 1966, he was arrested based on his confession and a tiny amount of blood and gasoline found on a pair of pajamas he owned.

"[9]Prosecutors put aside the pajamas and instead presented five pieces of bloody clothing that were found in a tank at the miso factory in August 1967, 14 months after the crime.

[13] Hakamada supporters said the case was full of holes, arguing that the alleged murder weapon – a fruit knife with a 12.19-centimetre (4.80 in) blade – could not have withstood the forty stabbings of the victims without sustaining significant damage, and that the pajamas used to justify the arrest had disappeared and been replaced with the bloody clothing.

In the investigation, it was determined the alleged murder weapon was the wrong size to produce the stab wounds, that a door supposedly used to enter the home was actually locked, and that the bloody pants were too small to have been worn by Hakamada.

[9] Backed by the Japanese Federation of Bar Associations [ja] (JFBA), Hakamada's lawyers concluded the first trial had failed to establish that any of the clothing belonged to him.

[9] In November 2006, 500 supporters, including world champion boxers Koichi Wajima and Katsuo Tokashiki, submitted letters to the Supreme Court asking for a retrial.

[21] The revelation came in spite of a strong tradition against publicly revealing discussions between judges, and it resulted in Kumamoto being highly criticized.

[21] After Kumamoto's statement, a campaign to retry Hakamada gained momentum, led by Amnesty International and the Japan Pro Boxing Association.

[11] American boxer Rubin Carter, who served 20 years on murder charges that were eventually overturned, and British actor Jeremy Irons spoke out on Hakamada's behalf.

On 25 March 2008, the high court denied the request, stating that neither the original or new evidence provided any reasonable doubt of Hakamada's guilt.

[17] A 2008 DNA test suggested the blood on the clothing used as evidence did not match Hakamada's, prompting a second retrial request from his lawyers.

[18] A statement from the court said there was reason to believe evidence had been fabricated in the original trial and that keeping the 78-year-old jailed while waiting on the retrial would have been "unbearably unjust".

Amnesty International remarked, "Time is running out for Hakamada to receive the fair trial he was denied more than four decades ago.

[16] According to a family member, Hakamada's mental health had badly deteriorated due to years in solitary confinement.

[9] A 2009 report on the death penalty in Japan by Amnesty International said a psychiatrist had diagnosed Hakamada with "institutional psychosis".

That August, prosecutors urged the Supreme Court to reject Hakamada's appeal to "stop the situation in which the sentence is suspended unnecessarily".

Hakamada's case caused people to question the validity of the death penalty and brought attention to what critics describe as "inhumane" elements of the Japanese justice system.

[11] The vast majority of miscarriage of justice cases in Japanese capital punishment cases involve police faking the investigative record to make it appear as if the suspect confessed certain guilty secrets, which only the perpetrator of the crime could have known and it later became apparent that the suspect was being forced to sign a completely blank confession paper which the investigative police filled in for their convenience.

Using his case and others, they argued "Japan's death row system is driving prisoners into the depths of mental illness".

[36] His legal team has now submitted the claim to the Shizuoka District Court, seeking financial redress for what remains the longest-known wrongful imprisonment in Japan’s history.