A nightclub waiter took part in a gang attack that left a customer dead, then washed the blood off his hands and finished the rest of his shift.

Shawalludin Sa'adon, 27, rallied together members of his secret society to confront 35-year-old Satheesh Kumar Manogaran, following an argument over a liquor bottle in the Postbar club at St James Power Station.

Shawalludin punched and kicked Mr Satheesh, who was stabbed by gang member Muhammad Khalid Kamarudin, 22, and later died of his injuries in March last year.

He was convicted of voluntarily causing grievous hurt yesterday. His mitigation plea and sentencing are expected to take place on Oct 8.

Deputy Public Prosecutor Andre Chong told the court that Shawalludin got into a row with Mr Satheesh at about 4.30am on March 12 last year when the latter and his friends left a liquor bottle on the floor, which they were not supposed to do.

To defuse the situation, Shawalludin's supervisors told him to step out of the premises to prevent further misunderstandings.

But the waiter felt aggrieved by his treatment, and called members of his secret society based in Toa Payoh Central to ask for back-up to confront Mr Satheesh.

Gang member Muhammad Hisham Hassan, 28, a former assistant restaurant manager, messaged others, including part-time mover Khalid and Muhammad Faizal Md Jamal, 23, who was serving his national service at the time.

When they arrived at Postbar at about 5.30am, Shawalludin identified Mr Satheesh and his cousin, Mr Naveen Lal Pillar, 29, to them.

Shawalludin, Khalid and Faizal confronted Mr Satheesh and Mr Naveen as they were about to get into a private-hire car.

Khalid - who was carrying a foldable knife - punched Mr Satheesh in the face, and then stabbed him once in the forehead, twice in the back of the head and twice in the back. Shawalludin and Faizal then punched and kicked Mr Satheesh and Mr Naveen.

After the attack, Khalid and Faizal fled in a taxi, while Shawalludin returned to Postbar, washed the blood off his hands and went back to work. He later found out from his colleagues that Mr Satheesh had died from his wounds, and informed Hisham. After his shift ended, he returned to his Marsiling Road home, where he was arrested by police.

Hisham was sentenced to 18 months' jail on Jan 2 this year, for harbouring Khalid at his godmother's flat in Yishun following the incident.

For voluntarily causing grievous hurt, Shawalludin could be jailed up to 10 years, fined and caned.