He pretended to be a Central Narcotics Bureau (CNB) officer to get cigarettes from strangers but when they doubted him, he slapped one of them.

Muhammad Farmi Sudin, 27, was sentenced to 10 weeks' jail and fined $4,000 yesterday for a range of offences, including the slapping and the attempt to impersonate a public servant.

A court heard that Farmi, who works as a mover, was at an East Coast Park chalet on May 4 last year with two friends, Ms Eunice Ng, 19, and Mr Muhammad Taufiq Djumadi, 26. At around 5am, they went out to buy cigarettes but all the shops were closed.

On their way back, they noticed four men in their 20s sleeping on benches near a barbecue pit.

Farmi approached one of them, Mr Ramachandran Anandan, 28, told him he was a CNB officer and demanded to see his identity card.

When Mr Ramachandran refused and asked to see Farmi's official ID card instead, Farmi slapped him. The commotion woke up the other three men. Farmi then ordered all of them to produce their identity cards, and demanded cigarettes from them.

Meanwhile, Ms Ng tried to seize a bottle of wine from the victims, claiming that it was an "exhibit". They left only when one of the victims called the police.

Farmi also pleaded guilty to threatening a police officer at Pasir Panjang MRT station on Nov 8 last year. Special Constabulary Corporal Muhammad Nabeel Rahman, 21, had stopped Farmi and his brother on a Circle Line train for suspicious behaviour.

When he ordered them to alight at Pasir Panjang, Farmi hurled vulgarities at him and tapped the policeman's face twice, threatening to beat him up.

Farmi showed up in court four hours late yesterday, claiming that he thought his hearing was the next day. For impersonating a public servant, he could have been jailed up to two years, fined, or both. For voluntarily causing hurt, he could have been jailed up to two years, fined up to $5,000, or both.