NARATHIWAT - A manhunt was launched for an armed suspect after two Tak Bai police investigators were killed and three others wounded during a drug search in Tak Bai district on Sunday.

The attack occurred about 11.48am at a hut in a palm plantation in Ban Bueng Chalam village in tambon Phrai Wan. Investigators from Tak Bai police station were conducting a search linked to a drug case when at least one gunman opened fire with an M16 rifle.

Two officers were killed and three others injured in the ensuing gunfight.

Those killed were Pol Sgt Maj Humran Ha, an investigator at Tak Bai who suffered multiple gunshot wounds to the chest and body, and Pol Snr Sgt Maj Witthaya Chaipromkaew, another investigator, who was fatally shot while pursuing the suspect near a bridge leading to the hut.

The injured officers were identified as Pol Lt Kittipong Srikham, who sustained a graze wound to his left side; Pol Cpl Traitos Kunsanthawasiri, who suffered a bullet graze to the head; and Pol Snr Sgt Maj Wannuchit Saekho, who was shot in both legs. All were initially treated at Tak Bai Hospital before being transferred to Naradhiwas Rajanagarindra Hospital.

Police said the fleeing suspect was shirtless and wearing track pants and was armed with an M16 rifle. He fled into the surrounding palm plantation and remained at large as of late Sunday afternoon.

Investigators recovered at least 10 spent M16 cartridge cases from three locations around the hut and plantation. Three other men believed to have been staying at the hut were detained and taken to the Paramilitary Marine Regiment in Tak Bai district for questioning to determine whether they had any connection to the shooter. (Story continues below)

Three men believed to have been staying at a hut near the attack site are questioned by authorities in Tak Bai district, Narathiwat, on Sunday, as a military helicopter joins the hunt for the fugitive gunman.

According to investigators, Pol Lt Kittipong had led a six-member team to the village to gather information relating to drug activity. As the officers were returning to Tak Bai police station, they noticed a group of men gathered at a hut and several motorcycles parked nearby.

Stopping to investigate, officers crossed a drainage ditch and approached the hut. Police said a gunman opened fire without warning, fatally wounding Pol Sgt Maj Humran. The team moved in to apprehend the shooter, who fled into the plantation.

Pol Snr Sgt Maj Witthaya chased the gunman, and was shot multiple times, the suspect taking cover behind a palm tree. A firefight followed, resulting in three more officers being wounded before the gunman escaped.

Pol Lt Gen Piyawat Chalermsri, commissioner of Provincial Police Region 9, ordered a joint operation involving police, military and administrative officials to seal off the area and track down the suspect, who was believed to still be hiding in the plantation.

Authorities declared the area a danger zone and barred unauthorised people, including reporters, from entering.

A police source at Tak Bai station said the gunman may not have been one of the men living at the hut. He may be a member of an insurgent group who had been staying there temporarily, coercing the occupants into giving him shelter.

The source said the suspect may have opened fire because he believed the police were there to arrest him. That had not been confirmed.

The search for the shooter was continuing.