SINGAPORE - Three Central Narcotics Bureau (CNB) officers had worked together in a plan to tamper with the urine sample of a drug abuser deemed to be a difficult subject.

According to the prosecution, one of them, Muhammad Zuhairi Zainuri, suggested that they should tamper with 32-year-old Maung Moe Min Oo's urine sample to expedite the drug abuser's departure from the CNB office.

Mohamed Hafiz Lan, another officer, urinated into a bottle and left it in a toilet so that Maung's urine sample could be substituted with his.

Hafiz and a third officer, Abdul Rahman Kadir, escorted Maung to the toilet where Hafiz told the drug abuser to urinate into another bottle before getting rid of its contents.

Hafiz's urine sample was then used in Maung 's drug test.

The Singaporean drug offender was allowed to leave after no trace of drugs was found in the sample.

Following a trial, Zuhairi, 34, and Abdul Rahman, 46, were each convicted on Thursday of one count of engaging in a conspiracy to intentionally obstruct the course of justice. They had earlier been suspended from July 2019.

In a statement to The Straits Times on Thursday, CNB said that Zuhairi resigned in February while Abdul Rahman is still under suspension.

Its spokesman said that CNB will start disciplinary proceedings against Abdul Rahman following his conviction, with a view to dismiss him from service, adding: “Officers are expected to maintain a high standard of integrity. Officers who break the law will be dealt with in accordance with the law.”

Hafiz, then 41, was sentenced to 18 months' jail in August 2020 after he pleaded guilty to a similar charge.

Deputy Public Prosecutors Alan Loh and Thiagesh Sukumaran stated in their submissions that Maung and a Thai woman were at the Woodlands Checkpoint at around 11pm on Aug 15, 2018, when they were detained for suspected drug consumption.

Maung knew that he would fail his drug test as he had earlier consumed methamphetamine.

The prosecution said: "As an ex-drug offender who had been sent to a drug rehabilitation centre (DRC) previously, Maung also knew that if his urine again tested positive for illegal drugs, he would be sent to the DRC for a second time.

"Maung feared that if he was sent to the DRC again, his wife would leave him, and he would lose custody of his two children."

In earlier proceedings, the prosecutors said: "While they were in the interview room, Maung requested Abdul Rahman's assistance in helping him pass the IUT (instant urine test) because he knew that his urine would test positive for methamphetamine, which he had consumed earlier.

"Meanwhile, Zuhairi left the interview room to speak to Hafiz at 12.17am, and they agreed that they would tamper with Maung's urine sample by swopping it with another sample that would produce a negative IUT result to expedite his departure from the CNB office."

The DPPs told Principal District Judge Victor Yeo that Hafiz urinated into the bottle and walked out at 12.20am.

Instead of Maung's urine, Hafiz's sample was then used to test for drugs.

Maung and the Thai woman later passed the urine tests and officers from the Immigration and Checkpoints Authority escorted the pair out of the CNB office at around 1.20am. The pair then left for Malaysia.

The offence came to light when a different CNB team detained Maung at the Woodlands Checkpoint on Aug 17, 2018.

The DPPs said: "The conspiracy was subsequently unravelled when Maung explained that Abdul Rahman had helped him pass his previous IUT which was administered (the day before)."

Maung's urine was later found to contain traces of methamphetamine and he was detained at a DRC.

During the trial, Zuhairi who was not represented by a lawyer, elected not to provide any explanation with respect to the charge against him and chose to remain silent when called to present his defence.

Defence lawyer Peter Fernando represents Abdul Rahman. In his defence, Abdul Rahman stated that he was unaware of the urine swopping plan and was not part of it.

On Thursday, Zuhairi told the court that he intends to file an appeal. DPP Loh, however, said that Zuhairi has zero prospects of succeeding in the appeal. The prosecutor also told the court that at the next hearing, he would object to Zuhairi to be given a bail pending appeal.

The case has been adjourned to Nov 16 for Zuhairi and Abdul Rahman's mitigation and sentencing.