CNN  — 

A Chinese man convicted of murdering two children has had his conviction overturned after serving 27 years in prison, in what has been described as one of the longest-serving miscarriages of justice in recent Chinese history.

Zhang Yuhuan, 53, was freed on Tuesday after the Supreme People’s Court in eastern Jiangxi province found him “not guilty” on the basis of a lack of sufficient evidence, Chinese state media Global Times reported.

The result came after a long-running legal battle to overturn the conviction, and highlights ongoing issues within China’s legal system.

In 1993, two boys were found dead in the city of Nanchang, Jiangxi province, according to the report. Police suspected the boys’ neighbor Zhang of killing them.

In 1995, Zhang was sentenced to death with a two-year reprieve, meaning his death sentence would be commuted to a life sentence if he didn’t commit any other crimes within a two-year period, state-run China Daily reported.

But Zhang appealed to a higher court, arguing that he was not the killer and claimed that police had tortured him during interrogation, according to the report.

The higher court ordered a retrial, but that was not held until November 2001, China Daily reported. The intermediate court upheld the original judgment, and a later appeal was rejected.

Zhang and his family continued to insist that he was innocent – and finally in March last year, the Jiangxi Supreme People’s Court reopened the case, according to the report. On Tuesday, he was found not guilty.

“After we reviewed the materials, we have found there is no direct evidence that can prove Zhang’s conviction. So we accepted the prosecutors’ suggestion and have declared Zhang innocent,” judge Tian Ganlin was quoted as saying.

Zhang can now apply for state compensation, Global Times reported.

According to the China Daily report, Zhang said the wrongful conviction had cost him the best years of his life. His two sons are now married and have their own children.

“It’s hard for the compensation to make up for the damage of the wrongful conviction to me and my family, but I still hope to get compensated quickly to repair my house and care for my mother,” Zhang said.

Criminal justice

For years, human rights advocates have criticized China’s legal system, alleging that it allows unfair trials, torture and other ill-treatment in detention.

China has made attempts to reform its legal system. According to the Global Times report, China officially adopted the legal principle of “innocent until proven guilty” in 1996.

In 2013, an influential Communist Party legal commission issued new guidelines asking for fairer due process in China’s much maligned court system.

However, problems with the country’s legal system remain. China’s judicial system has a conviction rate of around 99%, according to legal observers. It also remains beholden to the ruling Communist Party. Courts are seen first and foremost as a “political organ,” according to the country’s Chief Justice Zhou Qiang.

It remains uncommon for people to have convictions overturned – although Zhang is not the first.

In 2013, a man who served 17 years of a life sentence for murdering his wife was freed after a Higher People’s Court in Anhui province ruled that the “facts about the alleged homicide were unclear and the evidence inadequate.”

In 2016, China’s top court overruled a rape and murder conviction of Nie Shubin – more than two decades after he had been executed.

Ruan Chuansheng, a law professor at the Shanghai Administration Institute, said that the ruling in Zhang’s case showed the advancement of the rule of law, according to China Daily. But he also said judicial authorities could help prevent wrongful convictions by excluding evidence gained through torture.