The 45-year-old suspected attacker, Cheung, turned himself in at a police station one hour later. Sources said Cheung has multiple criminal records and in 1999 was sentenced to eight years in prison for beating a 22-year-old triad member to death.

At about 2am yesterday, Cheung asked the victim for cigarettes but was turned down. He pulled out a fruit knife and stabbed the man in his stomach before fleeing, sources said.

A female passer-by saw the victim with a knife sticking in his abdomen and a blood stain on his white shirt staggering across a road in Sham Shui Po. She called in police and the victim was rushed to a hospital.

The victim, Ng, who scavenged for items to sell to make a living, was resting opposite the public open space on Pei Ho Street when a fat man, Cheung, suddenly approached him to ask for cigarettes.

But when Ng refused, Cheung got angry and allegedly stabbed him with a fruit knife in the right abdomen. Ng was taken to Princess Margaret Hospital.

The source said Cheung went to Sham Shui Po police station at about 3am to turn himself in. Cheung is unemployed, living in no fixed place, and was taken into custody.

It is understood that the suspect has committed many crimes. He was arrested for cat abuse in 2017. Cheung tied up a three-month-old kitten with plastic straps, leaving it injured in a vacant lot in Wong Nai Tun Village, Tai Tong.

He pleaded guilty to animal cruelty and was sentenced to 10 days in prison. The court also revealed that Cheung had nine convictions at the time.

The most sensational case involved a gangland murder in 1999. Cheung and five men fatally abused a 22-year-old triad member, including punching, stabbing and setting him on fire. The body was wrapped in plastic bags and hidden in a cardboard box.

Cheung was later arrested and pleaded guilty to aggravated assault with intent and was sentenced to eight years in prison.