SINGAPORE - The Singapore Police Force (SPF) has reviewed its screening processes for future potential officers following recent cases in which two policemen were found to be secret society members.

Without revealing details, it said in a statement that the force conducts vetting on shortlisted applicants for police jobs.

An SPF spokesman added: "Notwithstanding these measures, we recognise that we may not always detect the adverse background of all the applicants...The SPF has also reviewed our screening processes to minimise the possibility of similar cases from falling through the gaps again in future."

On Thursday (May 31), a senior staff sergeant attached to Ang Mo Kio Division admitted in a district court to being a senior member of a secret society, and the headman of a motorcycle gang.

Umar Hassan, 38, pleaded guilty to two counts of being a member of an unlawful society. Two other charges for similar offences will be taken into consideration when he is sentenced on June 20.

Umar had set up his motorcycle group with three others in 2001. He was later recruited into and made a senior member of his other gang six years later.

In October 2008, he approached the assistant headman of this second secret society to get his motorcycle group to be affiliated to it. The assistant headman agreed to this arrangement, the court heard. Court documents did not state when Umar joined the SPF. He was arrested on Nov 18, 2016 after police learnt about a video clip which showed a group of men chanting gang slogans at a wedding.

His Facebook page, laptop and mobile phones were later found to contain pictures of him displaying a hand sign to show that he was a gang member. Umar has been suspended from service in the SPF from Dec 14 last year.

In the statement, police said that after Umar's gang affiliation was discovered, officers conducted extensive investigations into his history, the extent of his secret society involvement, and whether he had attempted to recruit his colleagues.

The spokesman added: "We also thoroughly examined the information which he had access to and whether he had used it in a manner prejudicial to SPF, and law and order. Based on our investigations so far, there is no indication of such abuse."

Upon his conviction, police said they will start disciplinary proceedings against him, with a view to dismiss him from service.

On Wednesday, Muhd Firdaus Abdullah, 20, who had been serving his national service with SPF, was jailed for six years and two months with five strokes of the cane.

He had pleaded guilty in April to offences including harbouring an alleged murderer - Muhammad Khalid Kamarudin, 22.

Both Firdaus and Khalid were members of the same secret society. Khalid's case is still pending.

The two men and Umar belonged to different gangs.