A brothel operator who was convinced that a pimp who worked for him had stolen his money summoned the suspected culprit to see him, intending to force a confession out of him.

Maintaining his innocence, the pimp, William Tiah Hung Wai, decided to show up despite advice from a co-worker not to go because their boss, Chan Lie Sian, might turn violent.

At the brothel, a lodging house in Lorong 18 Geylang, Chan repeatedly struck Mr Tiah on the head with a metal dumbbell rod even as he fervently denied stealing the $6,500, until he lost consciousness.

Mr Tiah died seven days later in hospital, a day short of his 36th birthday.

Yesterday, Chan, 53, was sentenced to the mandatory death penalty after he was found guilty of murder with intention to cause the victim's death between 11am and 2.30pm on Jan 14, 2014.

During his trial earlier this year, Chan, who was represented by Mr Kelvin Lim, contended that he struck the victim only twice and that the blows were accidental. He also argued that he was intoxicated after taking sleeping pills and cough syrup.

But Deputy Public Prosecutor April Phang argued that medical evidence showed that Chan's attack was "vicious and relentless", indicating his intention to kill.

An autopsy found about 10 blows to the victim's head, resulting in fractures that ran all the way to the base of the skull, with fragments embedded in the victim's brain.

The DPP argued that Chan's actions after beating up the victim corroborated his guilt. Chan warned his workers not to report the case or call for an ambulance, and also told them to throw away the rod and to clean up the bloodied room.

He later lied to the police about the whereabouts of the murder weapon, leading investigators on a wild goose chase when he took them to a spot along the Kallang River, where he claimed he had tossed the rod.

Judicial Commissioner Hoo Sheau Peng rejected Chan's account and found that he had hit the victim's head at least nine times with the intention to cause death.

She agreed with the prosecution that the attack was vicious and one-sided against an unarmed victim who was smaller.

Chan was persistent in his attack; he hit the victim in the living room and continued as he pursued him into a room at the lodging house.

She added that after the victim became unconscious, Chan continued striking him, uttering in Hokkien that if he was not dead, Chan would break his arms and legs.