CHIANG MAI resident Sakharin Karuehas, who was detained for allegedly setting fire to a department store in Nakhon Si Thammarat, will face another serious charge of possessing an explosive substance in connection with the bombings and arson attacks last week, a police source said yesterday.

There has been widespread speculation that Sakharin, who works on an oil rig in the Gulf of Thailand, was wrongfully arrested because his image was captured by a closed-circuit camera. He is currently being detained under the absolute power granted by the interim charter’s Article 44 but the source said he would soon be transferred to police custody.

Deputy police chief Pol General Sriwara Rangsiphrammanakul told Nakhon Si Thammarat police to revoke the previous arrest warrant against Sakharin on the arson charge and collect evidence for the new allegation of possessing explosive materials, the source said.

Sriwara would seek an arrest warrant from a military court to extend the suspect’s detention, according to the same source.

Sakharin was arrested on Saturday at the oil rig where he works after a string of bombings rocked Prachuap Khiri Khan and six southern provinces, including tourist spots such as Phuket, Samui and Hua Hin, on Thursday and Friday. The attacks killed four people and injured more than 30 others, including foreigners.

Sakharin’s arrest has been widely questioned because of the perceived paucity of evidence.

Deputy Prime Minister Prawit Wongsuwan defended the arrest, saying the image captured by CCTV indicated that Sakharin was guilty. “Don’t say we got the wrong guy, that is not true. Our investigation has made some progress. Don’t put pressure on officials,” Prawit told reporters yesterday.

Human rights groups have also questioned an arrest warrant issued for a suspect from Narathiwat’s Tak Bai district.

Cross Cultural Foundation director Pornpen Khongkachon-kiet said the police’s evidence gathering and suspect identification methods were unclear, leaving room for speculation about the integrity of the investigation.

An arrest warrant was issued on Tuesday for Ahama Lengha, the suspect from Tak Bai district, who allegedly was responsible for planting a bomb at Phuket’s Patong Beach. The bomb was detected before it was detonated.

“There is doubt about how the police collected the evidence from the bomb site in Phuket and linked it to the suspect from the Tak Bai incident in 2004,” said Pornpen, who works intensively on cases in the deep South. “So it is still unclear where the evidence came from and its validity.”

The Tak Bai incident refers to the killing of four protesters in the district in October 2004, and the subsequent deaths of another 78 protesters who were suffocated or crushed to death while being transported by authorities to Pattani province.

In her experience, Pornpen said officials usually picked up unrelated materials at crime scenes such as cigarette butts, which were used to identify suspects who might not be involved in the case, but are subject to interrogation under special security laws.

Meanwhile, Sittipong Chantra-raviroj, secretary-general of the Muslim Attorney Centre, said he might provide legal assistance to Ahama to help to protect his rights.

Authorities have been struggling with the investigation since the bombing and arson attacks last week with many theories about the attacks, ranging from domestic sabotage connected to the August 7 referendum on the draft constitution to the insurgency in the predominantly Muslim deep South.

The government has sought assistance from Malaysia after finding a Malaysian mobile phone and SIM at one of the crime scenes in Phuket that might have been used for detonation.

Prime Minister General Prayut Chan-o-cha yesterday said Malaysian authorities had already received evidence from their Thai counterparts, but he had not talked to Malaysian Prime Minister Najib Razak about the investigation while he was in Kuala Lumpur for a conference on Tuesday.

However, Malaysia’s Bernama news agency yesterday quoted Malaysia’s Inspector-General of Police Khalid Abu Bakar as saying preliminary investigations had not yet determined whether the SIM card had originated in Malaysia.

Meanwhile, a combined military and police taskforce yesterday arrested an unidentified man at Pattani’s Nong Chik district hospital based on information provided by another man who was arrested in Krabi, which was also the target of a bombing last week.