SINGAPORE - A 49-year-old man has been sentenced to death for heroin trafficking after the High Court rejected his contention that the majority of the drugs found in his apartment belonged to his 26-year-old girlfriend.

Mohamed Ansari Mohamed Abdul Aziz, a Singaporean, and his 26-year-old Indonesian girlfriend, Bella Fadila, were arrested by Central Narcotics Bureau (CNB) officers on March 24, 2016.

A search of the couple's rental apartment at Vibes @ East Coast found 77 packets containing more than 760g of a granular substance.

The substance was found to contain 30.23g of pure heroin after analysis. The law provides for the death penalty if the amount of heroin trafficked exceeds15g.

Ansari initially claimed that Bella was not involved, but later incriminated her for helping to pack the drugs.

During his trial, Ansari alleged that 16.51g of the heroin belonged to Bella and that only 13.72g, below the threshold for capital punishment, was his.

Justice Valerie Thean, who convicted Ansari on July 22, said in written grounds issued on Monday that the prosecution had proven beyond reasonable doubt that Ansari was in possession of all the drugs.

"The accused's statements clearly indicated that he was in possession of all of the drugs. His contradictory narrative in the courtroom was not credible. I accepted Bella's evidence that her only role was to assist with packing the drugs," said the judge.

Justice Thean imposed the death penalty on Sept 19, after finding that Ansari was not a courier, which would qualify him for life imprisonment, but had admitted to selling five small packets of heroin for $350 to $400.

Bella is serving a 26-year jail term after she pleaded guilty in 2018 to a charge of possessing the drugs with the common intention of trafficking the drugs with Ansari.

She was called as a prosecution witness and testified that all the drugs belonged to Ansari and that she had helped to pack them at his request.

After his arrest, Ansari initially told CNB officers that his girlfriend was not involved.

He subsequently told officers in two statements, recorded on March 31 and April 4 that year, that she had helped him pack the drugs.

In the March 31 statement, he said: "For the heroin at home, I had asked her to help me pack the heroin into the small Ziplock bags. I think she had only packed less than 15 packets of heroin. The rest, I did it on my own."

Ansari later said he had incriminated her in his bid to obtain a certificate of substantive assistance, which could allow him to be given a life sentence and caning instead of the death penalty.

However, during his trial, which began in January 2022, he claimed that he had lied in these statements in an effort to help "save" her.

He claimed that he had downplayed her full role and took full responsibility, even though not all the drugs belonged to him.

The defence also sought to cast doubt on the veracity and credibility of Bella's testimony.

But Justice Thean said Bella had already been sentenced and even if she was prepared to lie to save herself, that was no longer relevant when she gave evidence at Ansari's trial.