Nagaenthran K. Dharmalingam, who was found guilty of trafficking a small quantity of heroin into the city-state, was executed on Wednesday after more than a decade on death row.
His case sparked widespread outrage, with critics including the United Nations and the European Union saying that hanging a person with intellectual disabilities violates international law.
Singapore insists the death penalty has helped make the country one of the safest places in Asia.
In Tanjung Rambutan, the 34-year-old’s hometown in northern Perak state, around 250 mourners gathered at his home to pay their last respects, according to an AFP reporter.
Nagaenthran was a member of Malaysia’s majority Muslim ethnic Indian Hindu minority and the funeral followed community traditions, with sobbing relatives laying flowers on his coffin.
Prayers were read, drums banged, and fireworks set off before the body was carried to a hearse for transport to a crematorium.
“My brother was a wonderful person and we will miss him dearly,” his sister Sarmila Dharmalingam told AFP.
“Our worst nightmares have come true.”
“My humble message to the world – please abolish the death sentence,” she added.
Nagaenthran was arrested at the age of 21 when he tried to enter Singapore with a bundle of heroin weighing about 43 grams – the equivalent of about three tablespoons.
Supporters say he has an IQ of 69, a level recognized as a disability, and was forced to commit the crime.
But Singapore has defended the execution, with its drug law enforcement agency saying Nagaenthran “knew what he was doing” when he committed the crime and the courts had found he had no intellectual disability.
Singapore resumed executions last month after a hiatus of more than two years, and activists fear authorities will launch a wave of hangings.
But there was relief on Thursday for another Malaysian convicted of drug-related offenses, Datchinamurthy Kataiah, after he won a bid to have his hanging postponed.
Datchinamurthy, who was found guilty of trafficking heroin into Singapore, was due to be executed on Friday but that has been postponed as he has another pending case in court.