A Taiwanese man has been sentenced to death in the final ruling of a 23-year-old murder case.

Chiou Ho-shun lost his final court appeal on Thursday. The man was convicted of the 1987 murder of nine-year-old Lu Cheng, who was kidnapped, dismembered and thrown into the ocean.

Chiou and his lawyers were appealing based on a number of irregularities in the case and initial investigation, but Taiwan's supreme court decided that the charges would stand, finding that Chiou had a fair trial, according to the Taipei Times.

He was also found guilty of the murder of an insurance agent in the same ruling.

At the time of his arrest, police reportedly extracted a confession using torture. There were eleven other suspects in the case, most of whom had charges dropped over the allegations. Chiou's girlfriend Wu Shu-chen was also found guilty of kidnapping the boy, and sentenced to 10 years in prison.

Two prosecutors and 10 police officers were fired for using violence and abuse to get confessions during the original investigation. Additionally, police omitted in trial that a man on death row confessed to the murder before his execution.

"The Taiwanese authorities must immediately halt the execution of Chiou Ho-shun, and order his retrial with fair proceedings in line with international standards." Amnesty International's Asia-Pacific Director Sam Zarifi insisted in a statement.

"Taiwan must also introduce a moratorium on all executions as a step towards abolishing this cruel, inhuman and degrading punishment outright."

Chiou's pro bono legal team said they would continue to petition to get the case re-examined.

Currently, there are more than 50 people on death row in Taiwan. Five men have been executed in 2011, and four more executed in April 2010.