Police are hunting three Uighur escapees who slipped out of an immigration detention centre in Sa Kaeo province in April to find out whether they are linked to the Erawan shrine and Sathon pier bombings.
A police source close to the blast probes said investigators are seeking more information about the trio.
Sa Kaeo Immigration Police deputy commander Benjapol Rodsawad said on Friday three Uighurs fled from the centre. They were among 20 Uighurs the Immigration Bureau in Bangkok — which earlier held about 200 Uighurs — sent to the Sa Kaeo immigration facility in March.
Seventeen slipped out of the detention centre on April 29, but 14 were later recaptured, he said.
The Sa Kaeo Court has issued warrants for the arrest of the three men who are still at large.
Sa Kaeo immigration police contacted local security officers to look for the three men, but failed to locate them, believing they may have left the province, he said.
Investigators received information that the escapees planned to meet at the Victory Monument in Bangkok, but police found no trace of the men, Pol Lt Col Benjapol said.
However, he said none of the three escapees were likely to be the suspect wearing a yellow T-shirt captured on CCTV cameras at the Erawan shrine bombing scene because photos of them did not match the image of the suspected bomber.
CCTV footage of a man seen dropping a bag into the water near Sathon pier on the night of Aug 17. A bomb exploded by the pier the next day.
The shrine bombing on Aug 17 killed 20 people and wounded 130, many of them foreigners. Another bomb exploded under water by Sathon pier the following day but caused no casualties.
National police chief Somyot Poompanmoung said on Friday investigators are "just trying to figure out all their suspicions" regarding the bombings.
Pol Gen Somyot also insisted police have not yet pinpointed any nationalities for the two suspected bombers.
But evidence showed the bombing incidents are linked, the police chief said without elaborating.
Pol Gen Somyot, meanwhile, said police have made the best use of special equipment sent from foreign countries in their probes. Police are still waiting for some equipment, which could be delivered within two weeks, to carry out technical work, he said.
The Criminal Court on Thursday approved an arrest warrant for the suspect in the Sathon pier bombing, a man in a T-shirt, based on an image captured by CCTV.
Deputy national police chief Chakthip Chaijinda said it is clear that he is the man who dropped the bomb into the canal before it exploded the next day.
He is an Asian man, aged 25 to 30 and about 170 centimetres tall, police spokesman Prawut Thawornsiri said.
Pol Gen Chakthip said the probes into the two blasts have made modest headway.
He said he asked the investigators to rely on CCTV cameras because witnesses' accounts may be confused.
Police have contacted City Hall to review more of its CCTV footage.
He said the types of explosive substances could be known within a few days, pending forensic findings.
Police have not yet established motives for the explosions, he said.
Pol Gen Chakthip said the first army region and the Metropolitan Police Bureau (MPB) have worked together to provide security with focus areas being Wat Phra Kaew, the Grand Palace, Ratchaprasong area and Asiatique.
Meanwhile, army commander Udomdej Sitabutr has called on the public not to jump to conclusions about who was behind the deadly shrine bombing.
"Believing what we have only seen unclearly, and analysing and jumping to conclusions would be misleading," said Gen Udomdej, who is also the deputy defence minister.
"It needs evidence, including CCTV footage or other material for a thorough analysis."
Foreign Ministry spokesman Sek Wannamethee assured yesterday that Thai authorities have not engaged in speculation as the investigation is ongoing.
Relevant information about the shrine blast has been announced by the National Council for Peace and Order to the public on a daily basis, he said.
MPB chief Sriwara Rangsipramanakul said police have questioned 200 witnesses regarding the two city explosions.