A policeman with a grudge allegedly killed his wife and father-in-law in a shooting rampage that left six people dead.

Police Sergeant Major Attaphon Wichian, 46, and a several other men armed with M16 rifles and shotguns stormed into to the house of his father-in-law Thammarong Nilniyom, 60, in Surat Thani province, Thailand, on April 8.

The attackers allegedly opened fire leaving four people dead in the ensuing chaos. The casualties were Thammarong, village council chief Pornsak Phetchshu, 56, and Pornsak's wife Nilthip Palakachen, 49.

Also dead at the scene was the shooter's elder brother Thammarat Wichian, 48, who was involved in the attack and is believed to have been shot in the crossfire.

The suspects fled in a Toyota Vios before police arrived.

Police Lieutenant General Surapong Thanomjit, commissioner of the Region 8 Provincial Police Bureau, said that Sergeant Major Attaphon had served at the Khirirat Nikhom district police station.

The Surat Thani Provincial Court has now issued arrest warrants for Attaphon and his alleged accomplice, Manop Wang-ngarn, 57, who is believed to have joined the shooting.

The investigating cop said: 'Thammarong had disapproved of Atthaporn's marriage to his only daughter Panida Nilniyom, 34. He wanted the couple divorced, possibly leading to the police officer's rampage.

'Friends and relatives have told us of many arguments between the two men. It was a very unhappy relationship.'

A day after the attack, a shocked Buddhist monk at the Wat Kraisorn Khet Raram temple in the Khao Phang district discovered another corpse inside a car.

The body was identified as 'Bas', 22, Atthaphon's son from his previous marriage. He was found next to the driver's seat with a gunshot wound on the head and his wrists bound with rope.

On April 10, Khirirat Nikhom police discovered yet another body. Attaphon's wife Panida was found dead in a room at the Leelawadee Resort. Staff found her body after they followed a foul smell coming from inside.

She was shot with a 9mm pistol with a silencer, making her the sixth alleged casualty in the cop's rampage. Officers believe she was the first victim, and had been killed on April 7.

Police found the suspects' Toyota Vios parked at a resort in the Ban Ta Khun District at around noon on April 10. There was no trace of Atthaporn, but they managed to arrest his accomplice Manop in Phang Nga province later in the evening.

Manop said that after the attack, he fled with the other suspects and was dropped off at a house in the Ban Takhun District, with Bas serving as their getaway driver.

He then escaped to the Thap Put District, fearing Atthaphon would hunt him down next.

Police said they are still searching for Atthaphon, considered the prime suspect in the case.