SINGAPORE - It was a case of mistaken identity.

A group of men thought cleaner Abdul Hamid Ahmad had attacked their friend, and pommelled him to take revenge.

The 48-year-old cleaner suffered multiple injuries, including cuts and a scratched eye, and spent a day in hospital.

One of the assailants, 22-year-old Nigel Koh Jia Sheng, was sentenced on Wednesday to two months in prison for being part of an unlawful assembly to hurt Mr Abdul Hamid on Jan 31 this year. Four other men, aged between 20 and 24, have also been charged and their cases are pending.

The court heard that together with other friends, the five had celebrated Chinese New Year at Club Gossip in St James Power Station.

They were smoking underneath an overhead bridge when they heard a group of men shouting from the bridge. Mr Abdul Hamid, who also happened to be there, was not part of the group.

Koh and two others went up and saw a friend on the ground being attacked by a group of men, who then ran into Vivocity mall nearby after being confronted by another unidentified group.

The five joined the chase and entered Vivocity, where they saw Mr Abdul Hamid being attacked by the second group outside a convenience store.

Believing the cleaner was among those who had earlier attacked their friend, the five assaulted him, with Koh kicking and punching the victim.

Koh could have been jailed up to two years and fined.