Four men have been detained over the killing of a policeman here on Sunday. A major breakthrough in the case came after two passports were found in the car abandoned by the assailants.

Police traced two of the suspects through the passports although investigations are continuing to ascertain whether the passports belonged to the assailants or were stolen.

One man was arrested at a house in Tangkak yesterday morning while three suspects were picked up late last night after a raid on a mobile phone shop in Batu Pahat. All four are in their 20s.

Corporal Nik Manja Abdul Manaf was killed in the shoot-out with the robbers and Lance Corporal Razali Abu Bakar took a bullet in his shoulder when they responded to a tip-off of a burglary at a contractor’s house here on Sunday.

The four were produced before magistrate Emelia Kaswati Khalid here yesterday, who granted police a six-day remand order.

The robbers had abandoned their Proton Wira and escaped in the BMW belonging to the victim Lim Teng Hai. They had taken Lim’s son Siew Hock, 35, and his cousin, Neow Tun Teong, 32, as hostages.

Neow was released while Siew Hock was found gagged and tied at a shed in a durian plantation in Parit Limbong, near Parit Jawa, about 10km from the scene of the crime.

The BMW was also found abandoned at the durian plantation after its tyres sunk into a muddy patch and the robbers could not go any further.

Federal CID director Datuk Musa Hassan, who is leading the investigations here, confirmed the arrest of the four suspects but declined to elaborate.

"We are doing all we can to bring the robbers to book. We hope to wrap up the case soon," he told reporters at a ceremony where donations from the Malaysian Crime Prevention Foundation, Selangor branch for the two policemen were presented.

The foundation’s vice-chairman M. Jayabarathi handed over a personal donation of RM2,000 to Muar police chief Assistant Commissioner Daud Ahmad for Junaidah Parman (wife of Manja) and an undisclosed amount to Razali at the Muar Sultanah Fatimah Specialist Hospital.

Musa said police were in no position to disclose details as investigations were in progress.