Police are now targeting a local politician at municipal chief level in Songkhla who they think could be the head of a network trafficking Rohingya people.
The new focus comes after police on Monday arrested three local politicians and officials and a Myanmar national for alleged involvement in the human trafficking network.
The three officials are Arsan Intanu, a member of Sadao's tambon Padang Besar municipality council, Ro-ae Sonyalae and Ali Lamoh, both assistant village headmen in tambon Padang Besar. The Myanmar national was identified as Soe Naing Anwar.
Mr Anwar, 40, was arrested in Nakhon Si Thammarat in a different criminal case last Wednesday for allegedly demanding a ransom for a Rohingya man, believed to have been kept in the detention camp discovered in Padang Besar prior to last week's raid.
He is thought to be a core human trafficking broker in the South.
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They are among eight people wanted under arrest warrants for alleged links to the network.
The others are Prasit Lemleh, deputy chief of tambon Padang Besar municipality, Yali Krem, a village headman of Moo 8 in tambon Padang Besar, Charoen Thongdaeng and Pakapol Benlatae.
National police chief Somyot Pumpunmuang said he had assigned investigators to quickly apprehend a man who they believed shot dead two Rohingya late last year in the area, adding that the person could provide information to authorities on whether a local municipal chief had links to human trafficking.
Pol Gen Somyot also said he would sign orders to transfer five high-level officers at Padang Besar police station, including its superintendent Pol Col Weerasan Thanpiam, and those in the border patrol police unit to the Royal Thai Police Operation Centre.
In addition, the police chief said he would sign an order to transfer Pol Maj Gen Sunthorn Chalermkiart, commander of Satun police, to the operation centre, saying the commander is closely associated with a prime network suspect in Satun.
Satun is one of the five coastal provinces by the Andaman Sea, where Rohingya are believed to illegally enter Thailand by boat.
The arrested suspects all face charges of human trafficking, detention and ransom. Another charge of carrying a firearm in public places without permission has also been laid against Mr Arsan. When arrested, Mr Arsan had in his possession a 9mm handgun with eight bullets.
Mr Arsan, Mr Ro-ae and Mr Ali denied the charges, according to officers.
Pol Gen Somyot said he was assigned by Prime Minister Prayut Chan-o-cha and his deputy Prawit Wongsuwan to follow up the case in Songkhla.
The premier and his deputy attach great importance to the case since it is tarnishing the country's image and its efforts to solve the human trafficking problem.
Pol Gen Somyot said the premier ordered the arrests of anyone involved with the case.
Responding to a reporter who noted that a border patrol police post was not far from the discovered detention camp, the police chief said a probe will be carried out to determine whether the officers had links with the illicit network and gave assistance or received benefits.
The officers would also be punished if they are found to have turned a blind eye to the matter, he said.
"It is now clear the detention camp and bodies are linked with a human trafficking network, which is a transnational one," the police chief said.
Also on Monday, officers discovered between three and five places where more bodies were suspected to be buried, about 200 metres from the mass burial site in the detention camp.
Police and other officials will dig up those areas today.
Citing deputy national police chief Ake Angsananont, who is responsible for the investigation, Pol Gen Somyot said buildings found in the camp suggested a huge number of Rohingya were relocated there, adding that the camp had been running for many years.
He said another police team, led by Pol Gen Chakthip, will also contact Malaysian and Myanmar authorities to seek cooperation in pursuing the illegal network, adding that the police Special Branch will take an active part in tackling the problem.
The transnational criminal network involves Thai, Myanmar and Malaysian nationals and it had been running for at least three or four years, he said.
Speaking about the 26 bodies, one of which was of a woman, exhumed from the site, the police chief said officers believed they had died from illness or lack of food, though the actual causes will be discovered via forensic investigation.
According to Pol Gen Somyot, three or four more suspects will face arrest warrants in connection with the case.
Among them is an administrative officer who ran the camp, he said.