(CNN) -- Iwao Hakamada holds the most dubious of records: Convicted of a 1966 quadruple murder, he is the world's longest-serving death row inmate, according to Amnesty International. That record was capped Thursday when, after almost 48 years, a local court reopened Hakamada's case, Amnesty and Japanese media reported. The Shizuoka District Court suspended his death sentence and released Hakamada after DNA testing indicated key evidence against him may have been fabricated, reported NHK, the Japanese public broadcasting organization. The court said keeping him detained any longer would be unjust, NHK reported. Prosecutors have four days to appeal the court's ruling, but Amnesty International's East Asia research director said it would be "most callous and unfair" to challenge the court's decision.
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Iwao Hakamada served 48 years in prison for murders of his boss and boss's family
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Court granted him a retrial, saying some evidence may have been fabricated
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Amnesty international says he was beaten and threatened into confessing in 1966
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78-year-old ex-boxer's mental state deteriorated because of isolation, Amnesty says
Hakamada's case marks the sixth time a death row inmate in Japan has earned a retrial, and courts overturned death sentences in four of the five previous cases, @placeholder reported.