Myanmar’s opposition National League for Democracy (NLD) will ask the nation’s highest court to review the death of a party member it believes was killed during police interrogation, a party spokesman said Sunday.

Aung Hlaing Win, a 30-year-old NLD youth member, was arrested on May 1.

His family was informed his death 10 days later, but officials never revealed the cause of death and said his body had already been cremated.

His family members filed a complaint against police, but in June a township court ruled that he had died of a chronic liver illness while in police custody and not during interrogation.

A doctor had told the court Aung Hlaing Win’s body showed 24 injuries including bruises, the NLD said, but appellate courts have refused to reconsider the case.

In the latest rejection, the Yangon divisional court declined to hear the case Friday, NLD spokesman Nyan Win told AFP, adding that Aung Hlaing Win’s wife had decided to appeal to the Supreme Court.

“So his wife will continue to apply to the Supreme Court. Our NLD legal advisory committee will help her,” Nyan Win said.

“We will try to find out what happened in this case whether the Supreme Court accepts it or not,” he added.

Anti-Yangon exile groups have maintained Aung Hlaing Win died in custody after unknown agents abducted him from a food stall in downtown Yangon.

The Norway-based Democratic Voice of Burma said the commander of an interrogation centre had notified relatives that Aung Hlaing Win died of a heart attack during interrogation on May 7 and was buried two days later.