Police investigators for last week's Erawan shrine bombing, and the subsequent explosion at Sathon pier, have zeroed in on more than 20 Turkish nationals who entered Thailand within 15 days leading up to the shrine blast, according to a source.
The police are working together with the Immigration Bureau to find the personal data and backgrounds of the Turkish visitors, said the source.
The Immigration Bureau is comparing the photos of the Turkish nationals in their immigration records with the identikit, or police drawing of the suspect, and images of the shrine bombing suspect taken from security cameras.
The police team wanted to know if any of the Turkish visitors resembles the suspected bomber who is now wanted by the police, the source said.
At a meeting Wednesday, investigators focused on the theory that the suspected bomber, who looks central Asian, might be a Turkish national connected to Turkish extremist groups.
Early last month, some 200 Turkish demonstrators stormed and trashed the Thai consulate in Istanbul in protest at the deportation of more than 100 Uighur Muslims to China. The attack was likely instigated by a pro-terrorist group, the Grey Wolves.
The investigation of Turkish tourists comes despite the fact the government has played down the idea the Erawan shrine blast -- which killed 20 people and injured 130 -- could be linked to Uighur or Turkish extremist groups retaliating against Thailand's deportation of more than 100 ethnic Uighurs to China in July.
Police have inspected the taxi used by the alleged culprit (the driver reported to police on Monday evening for questioning) and found fingerprints belonging to nine different people in and on the car.
But the fingerprints did not match any foreign criminal suspects in the police database, and so could not be identified, said the source.
Police spokesman Pol Lt Gen Prawut Thavornsiri said police still do not know if the Erawan shrine bombing and the Sathon pier blast are linked, despite the fact the same ball-bearing shrapnel was found at both scenes.
"The two explosions had different objectives. The bomb at the Sathon pier did not mean to kill, unlike that at the Erawan shrine," he said.
Pol Gen Prawut said the Royal Thai Police are seeking the government's approval to purchase biometric scanning equipment for the Immigration Bureau.
The equipment can scan faces, fingerprints and the retinas of a person to detect if they match any criminal profiles.
Deputy Prime Minister and Defence Minister Prawit Wongsuwon said the investigation was moving forward but refused to go into detail about progress of the probe.
None of several possible motives explored for the attack has been ruled out, be it international terrorism, politics or religious extremism, said Gen Prawit.
In another development, the Rights and Liberties Protection Department is considering a proposal to pay financial compensation to the victims of the Aug 17 blast, said department director-general Narach Sawetanant.
Each family of the 20 dead victims is entitled to receive 150,000 baht, while the 58 injured victims will receive different amounts of compensation depending on the degree of their injuries, said Mr Narach.
In total, more than 60 million baht will be paid out to the 78 victims of the bombing attack, he added.
Meanwhile, the Fine Arts Department began repairing the Lord Brahma statue at the Erawan shrine that was partly damaged in the blast.
Sahaphum Phumtharitirat, deputy director-general of the department, said the statue was damaged in four places, most severely on its chin.
The repairs are expected to take nine days to finish, wrapping up by Sept 3, he said, adding that the day after it is completed, a celebration ceremony will be held. Visitors to the shrine are allowed to enter to worship the statue as usual, despite the presence of the department's craftsmen.