A Chiang Mai man allegedly implicated in the fire at a Tesco Lotus superstore in Nakhon Si Thammarat last week is expected to face fresh charges of arson and bomb possession.
The warrant for his arrest is set to be sought with the Military Court.
Sakarin Karuehas, 32, was arrested on Saturday on an offshore oil platform off Nakhon Si Thammarat where he worked. He was charged with committing arson at the store.
The attack was one of 13 bombings and arsons, which killed four people and injured 35 others in seven provinces last Thursday and Friday.
He is being held under an arrest warrant issued by the provincial court. His image was captured by closed-circuit surveillance cameras before the blaze began, a key piece of evidence that led to his being caught, police said.
Deputy national police chief Srivara Ransibramanakul said yesterday the provincial court warrant would be withdrawn as an investigation by Explosive Ordnance Disposal officers had found explosive devices were involved in the attack.
Based on a National Council for Peace and Order directive, suspects in such offences must stand trial in the Military Court.
Pol Gen Srivara, who leads the investigation into the case, said the new warrant against the suspect would be sought with the Military Circle 41 court based on counts on both arson and bomb possession.
The deputy police chief was speaking at Hua Hin police station, where he chaired a meeting to unravel the case yesterday.
Meanwhile, officers at the Military Circle 41, where Mr Sakarin was detained, took the suspect to Nakhon Si Thammarat police headquarters for further questioning.
Pol Gen Srivara said police have obtained solid evidence in connection with the bombings, which leads them to believe they have a greater than 50% chance to apprehend more suspects.
The deputy police chief said at least 10 suspects were believed to be behind the attacks.
The Military Circle 41 court has also approved a warrant for the arrest of Ahama Lenga from Narathiwat's Tak Bai district. A police source earlier said a sample of DNA collected from the Phuket blast matches his.
His DNA samples were collected twice. Mr Ahama was detained previously in connection with the Tak Bai protest in 2004 and six years later he turned himself in to authorities in connection with an alleged violation of the emergency law.
Meanwhile, police officers were deployed to search Mr Ahama's house yesterday morning.
His relatives told officers Mr Ahama left the house many years ago. He told them he was going to work in Malaysia, according to Pol Col Patcharapol Na nakon, chief of Tak Bai police.
Relatives have been unable to reach him since then, Pol Col Patcharapol said.
Deputy police spokesman Piyapan Pingmuang said investigators have not found any link to political groups in the probe, but insisted they cannot be ruled out.
He said police are working with Malaysian authorities to check Malaysian SIM cards in the mobile phones used to detonate the bombs, adding that part of the probe is going well.
Progress of more than 70% has been made in the investigation, Pol Maj Gen Piyapan said.
