Debts and death threats appear to be the motive behind the killings of eight people, including three children, at a house in Krabi's Ao Luk district last week, police said.
The suspected mastermind of the murders has been identified as Surikfat Bannopwongsakul, 41, a resident of Phangnga who was arrested along with seven others in connection with the family massacre.
National police chief Chakthip Chaijinda (second from right) and other senior police question the suspected mastermind of the Krabi massacre, Surikfat Bannopwongsakul, 41, with back to camera. (Photos provided by Royal Thai Police)
The arrests came about a week after the massacre on July 10 at the house of village headman Worayut Sanglang, 46, in tambon Ban Klang. Worayut, his wife, and their three daughters were among the victims. Three other people were wounded.
Suspected massacre mastermind Surikfat Bannopwongsakul, 41, claims the killings were over debts by the head of the murdered family.
Mr Surikfat, who ran a car and land mortgage business in Krabi, and Worayut were engaged in a financial row over a land mortgage, and they had a history of exchanging death threats.
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On the day of the massacre, Mr Surikfat planned to make it appear that Worayut was suffering from stress as a result of financial problems and had decided to kill everyone in the house and then turn the gun on himself.
"The assailants tried to make it appear that the village head had debt and family problems and decided to kill everyone," national police chief Pol Gen Chakthip Chaijinda told a press conference in Krabi.
None of the suspects was present at the press briefing.
The police chief travelled to the South for close supervision of the investigation and called in the media Sunday afternoon to confirm the arrests.
According to the police chief, the gunmen forced Worayut to call a friend and ask to borrow 500,000 baht, to support the story that he was in trouble, while Worayut's gun was used in the killing to frame him.
Pol Gen Chakthip said the other suspects who had various functions to perform during the killings, told police they were hired by Mr Surikfat to collect debts. They had been at the house twice to collect money.
Pol Gen Chakthip insisted the suspects are civilians who wore army camouflage outfits to storm the house and pretend to be security officers looking for something illegal.
He said police investigators would need a couple of days to conclude the investigation and forward the report to the prosecution.
"Based on the investigation, he [Mr Surikfat] is the one who pulled the trigger. I believe [the suspects] will be facing the death sentence," he said.
The national police chief said arrest warrants for the suspects, who are currently being detained under Section 44, are likely to be issued soon.
According to Pol Gen Chakthip, two other people were allegedly involved in the massacre but they were not at Worayut's house.
It was reported that one of them is Mr Surikfat's girlfriend who reportedly prepared the camouflage clothes. Pol Gen Chakthip did not disclose her name.
According to a source close to the investigation, Mr Surikfat confessed that he masterminded the killing and pulled the trigger. Three months before the killing, Mr Surikfat tried to abduct Worayut but failed.
The investigators got their break which led to the arrests when they showed a picture of one of the suspects to witnesses who also told them about a land mortgage deal involving Mr Surikfat.
They followed the lead and found that Mr Surikfat owned a vehicle similar to the one used in the crime. The investigation zeroed in on him after he appeared to go into hiding. The media outlets were told about the arrests on Saturday night.
It was reported the suspects were taken to the camp of the 15th Infantry Battalion in Krabi's Khlong Thom district for questioning. Mr Surikfat was arrested in Phuket on Saturday. The suspects were taken to a number of locations to retrieve pieces of evidence they had buried after the shootings.
After their arrest, two of the eight suspects led police to an area where guns and the burnt-out SUV of the dead village head were discarded.
At a house in Phangnga's Muang district police recovered SIM cards, memory cards, handcuffs, gloves, five .38 revolvers, one 9mm pistol, one .357 handgun, ammunition and one fake AK-47 rifle. Also recovered were coffee cans, camouflage shirts and empty water bottles.
Police also found a burnt Toyota Yaris car in Ban Nai Ngop village in Phangnga's Muang district. The car belonged to Worayut.
Authorities also searched a house in Nakhon Si Thammarat's Phra Phrom district, seized a car, and moved it to Krabi. The raid was led by Crime Suppression Division commander Pol Maj Gen Suthin Sappuang.
According to the source, the assailants went separate ways after the shooting. One drove off in the victim's Toyota Yaris sedan to Phangnga's Muang district and set it on fire.
The others fled in a Toyota Fortuner along Phetkasem Highway and in a white Toyota Yaris to Nakhon Si Thammarat.
The Fortuner was located in Bang Khan district and the white Yaris was seized by police from a house in Phra Phom district.
At a house in Bang Khan district, Nakhon Si Thammarat, authorities found four guns and a burned hard disc containing security camera footage.
Police believe they may be able to recover some data from the damaged disc.
Another team of police led by deputy national police chief Chalermkiat Sirworakhan searched a house in Krabi's Muang district said to belong to Mr Surikfat.
The house was reportedly used by the assailants before they headed off to Worayut's house and to which they returned after the shooting took place.
Below: Hero of the day - Residents presented Pol Gen Chakthip with flowers and heaped him with thanks at a makeshift ceremony after the successful hunt for the murder suspects.
