A night of festivity for two groups of foreign workers took a tragic turn when one group turned violent and, armed with weapons, attacked the other group, inflicting fatal wounds on one man.

The victim, Mr Boobalan Palanikumar, 28, died in hospital a day after the assault on Dec 31, 2012, in Jurong Lake Park. It had left him deeply comatose with extensive skull fractures and a swollen brain.

Yesterday, Raja Arul, 25, was jailed for three years and six months for his role in the unlawful assembly. His group had the intent to cause grievous hurt to seven people, including Mr Boobalan.

The court heard that at about 10pm on Dec 31, Mr Boobalan, a mechanical technician, arrived at a pavilion in the park with his friends.

Raja, a pipe fitter at the time, arrived at the park at about the same time with his friends.

The men are all Indian nationals.

As the night went on, Mr Boobalan's group got drunk. Some of them began shouting Tamil vulgarities, but these were directed at no one.

The second group, annoyed with the first, moved away from them but stayed within the pavilion.

Some time after midnight, one of Mr Boobalan's friends confronted Raja's group for staring at them. The two groups then separated and left the pavilion.

But, offended by the vulgarities used by Mr Boobalan's group, one of Raja's friends suggested beating up the other group. Five of the men then armed themselves by breaking off long wooden-pole supports from tree saplings in the garden.

The men, including an unarmed Raja, ran towards the other group. Mr Boobalan, who was lying drunk on the ground, was struck on his head and body. The assault lasted for about a minute.

When police officers arrived at 1.16am, they found some men lying at different locations in the park with various injuries.

Mr Boobalan was found motionless and bleeding profusely from a head wound. One of his friends had fractures to his eye socket and frontal sinus, while another had a dislocated joint in a forearm.

Two other men had lacerations to their skulls. Another two managed to escape injury.

Raja, who yesterday pleaded guilty to one count of rioting, had his jail sentence backdated to Jan 3, 2013, when he was first charged.

He and four others had originally been charged with murder, but later had their charges reduced.

The four men, aged between 28 and 34, face charges of voluntarily causing hurt with dangerous weapons, and voluntarily causing grievous hurt with dangerous weapons.

Their cases will be heard at a later date. If convicted, they face up to life imprisonment and caning.

Another two suspects involved in the attack fled Singapore on Jan 4, 2013. They remain at large.

For rioting, Raja could have been jailed for seven years and caned.