A Singapore court rejected on Tuesday an appeal against the execution of a Malaysian convicted of drugs smuggling, dismissing an argument put forward by his legal team that he should be spared because he was mentally impaired.
Nagaenthran Dharmalingam, 34, has been on death row for more than a decade for trafficking 42.7 grammes (1.5 oz) of heroin into Singapore, which has some of the world's toughest narcotics laws.
His plight has attracted international attention with a group of United Nations experts and British billionaire Richard Branson joining Malaysia's prime minister and human rights activists to urge Singapore to commute his death sentence.
Dharmalingam's lawyer Violet Netto had previously sought an independent psychiatric review for her client after objecting to presenting his prison medical records, citing confidentiality.
But turning down a request for an independent review, Chief Justice Sundaresh Menon said on Tuesday it had been unreasonable not to share the medical records and there was no admissible evidence showing any decline in his mental condition.
"The appellant has been afforded due process under law, and it is not open to him to challenge the outcome of that process when he has put nothing forward to suggest that he does have a case to be considered," the five-judge panel said in its ruling.
Dharmalingam, who was wearing a purple prison uniform, did not appear to show any reaction to the ruling.
His sister condemned the court's decision.
"We can't accept it, it's an unfair judgment for my brother. This is a heartless punishment," Sarmila Dharmalingam told Reuters.
Rights groups also called for Dharmalingam's life to be spared.
"The Singaporean government must act now to stop a grave travesty of justice from taking place and end its inhumane, shameful strategy of using the death penalty to address drug-related problems," Amnesty International said.
Anti-death penalty group Reprieve said it believed Dharmalingam is intellectually disabled and should be protected from the death penalty.
The Singapore government says the death penalty is a major deterrent against drug trafficking and that the majority of its citizens support capital punishment.
Dharmalingam has now exhausted his legal avenues in Singapore to escape the death penalty and a petition to the country's president for clemency had been denied.
Clemency for death row inmates is rare in Singapore and the country's leaders had sent a letter to their Malaysian counterparts to say Dharmalingam had been "accorded full due process under law".
It was not immediately clear when the execution would be carried out.
From 2016 to 2019, Singapore hanged 25 people - the majority for drug-related offences, according to official data.
(Reporting by Chen Lin in Singapore, additional reporting by Rozanna Latiff in Kuala Lumpur; Editing by Ed Davies)