TOKYO - A Japanese man said to have spent the world's longest time on death row was acquitted of murder on Thursday, broadcaster NHK said, ending his family's search for justice after a wrongful conviction for crimes committed nearly 60 years ago.

The Shizuoka district court cleared Iwao Hakamada, 88, in a retrial of the murders of four people in the central Japanese region in 1966, NHK said.

Hakamada spent 45 years on death row before a court ordered his release and a retrial in 2014 amid doubts about the evidence that formed the basis for his conviction.

The former boxer was accused of stabbing to death his former boss and family before burning down their home.

Though he briefly admitted to the killings, he retracted the confession and pleaded innocent during his trial, but was nevertheless sentenced to death in 1968, a penalty upheld by Japan's Supreme Court in 1980.

ALSO READ: Ghosn's arrest brings attention to Japan's 'hostage justice'

Norimichi Kumamoto, one of the three judges at the Shizuoka court who had sentenced Hakamada to death, petitioned the Supreme Court for a retrial in 2008, but the plea was rejected.

Hakamada's lawyers had argued that DNA tests on bloodstained clothing said to be their client's showed the blood was not his.

Since his release, Hakamada has lived with his older sister Hideko, who battled for decades to clear his name.

Rights group Amnesty International hailed the exoneration as a "pivotal moment for justice" and urged Japan to scrap the death penalty.

"After enduring almost half a century of wrongful imprisonment and a further 10 years waiting for his retrial, this verdict is an important recognition of the profound injustice he endured for most of his life," Amnesty said. 

READ MORE: Japan death row inmates sue over brief notice of execution

"It ends an inspiring fight to clear his name," it added in a statement.