A turf war between two underworld gangs is the reason behind the brazen killing of a man at a Johor Baru petrol station on Sunday, Malaysian officials said yesterday, as the manhunt for four assailants continued.

The brutal murder of the 44-year-old man, named as Tan Ah Choy by local media, has shocked Malaysians, with the authorities not discounting the possibility that it was an assassination.

The victim was stabbed and mowed over twice by a white BMW at the Taman Pelangi Shell station, about 4km from the Causeway.

"Yes, he was the leader of one of the gangs. It stemmed from a turf dispute between two rival gangs," Home Minister Ahmad Zahid Hamidi told reporters yesterday. "The four suspects who attacked the man have also been identified, police are hunting them down as we speak."

Asked about the possibility of retaliation from the murdered man's gang, Datuk Seri Zahid, who is also Deputy Prime Minister, said: "There is, since it involves secret societies. It is their nature to be vindictive, but the police are always ready. There is never a day without operations being conducted."

According to a media report, Tan had 13 previous drug convictions.

The Malay Mail Online news site said investigators from the Johor Baru South district police Criminal Investigations Department are looking into a possible drug dispute between the attackers and the victim as a possible motive for the murder.

Malaysian media reports said the victim had stopped his white Volkswagen at the petrol station, while his wife was inside the vehicle.

A white BMW 5-series car stopped nearby and four men alighted and began assaulting the victim. He was dragged to the assailants' car but he fought back.

An 82-second video clip of the incident recorded by a bystander showed that during the scuffle, an attacker stabbed him. Firecrackers were then thrown from the car towards where the victim lay.

The assailants' car circled the petrol station and ran over the man, before reversing and running over him again.

The car then sped out of the station, stopping briefly for one of the assailants to get in before fleeing.

The victim was seen conscious, media reports said, but was believed to have died while help was on the way.

Police said an autopsy showed the man died of a "stab wound to the heart".

The victim's wife on Monday took his remains from the morgue of Sultanah Aminah Hospital.

Asked at a function if Tan was indeed a gang leader, Malaysian deputy police chief Noor Rashid Ibrahim said: "We don't want to jump to conclusions, let us investigate first. Based on the information that we have, there's an involvement of money but we don't discount the possibility of it being a triad war."