BANGKOK: Thai authorities know who was behind a wave of bombings that rocked tourist destinations and killed four people, a police spokesman said Sunday, though officials remained tight-lipped on the details of their probe. At least two men have been held for questioning over the blasts in Hua Hin — a resort town struck by four of the bombs — and a third was arrested over a suspected arson attack in a separate province, police said. “Our investigation is progressing. We know who was behind it,” deputy national police spokesman Piyapan Pingmuang told AFP, declining to provide further details on those detained or a possible motive. A junta spokesman confirmed that multiple people have been questioned but stressed it was too early to identify them as suspects. “It’s just asking questions. They will not be treated as suspects unless the questioning procedure is done and any of them are found to have violated laws. Then legal action may be taken against them,” said Colonel Winthai Suvaree. At least 11 bombs and a series of suspected arson attacks ripped across seven southern provinces on Thursday and Friday, killing four locals and wounding more than 30 people, including European tourists visiting the country’s famed beaches. Some analysts suggest it was the work of Muslim rebels waging a long-running insurgency in Thailand’s southern tip. Thai officials have dismissed that theory and also ruled out international terrorist groups, insisting the bombings were acts of “local sabotage”. “We believe (the bombers) are still in Thailand,” deputy national police chief Ponsapat Pongcharoen told reporters Sunday. No one has claimed responsibility for the blasts, which are seen as an affront to a military government that prides itself on having brought some stability to Thailand since its 2014 coup. The kingdom has been battered by decade of political unrest, driven by a bitter power struggle between the military-allied elite and populist forces loyal to the ousted democratically elected government. Rounds of mass protests organised by the rival camps have been marred by streetside gunfights and grenade attacks. But the violence has not matched the coordinated nature of the latest bombings or targeted tourist towns. Analysts say the style of last week’s bombs mirrors those used by separatists in the far south. If the rebels are to blame, it would mark an unprecedented escalation of a 12-year revolt so far confined largely to the border region. The attacks came only days after the junta won a referendum vote on a controversial new charter it drafted. The document, which critics say will make Thailand less democratic, was approved by 61 percent of voters but rejected in the north and northeast — strongholds of the ousted government — and in the three insurgency-torn southern provinces. Thailand’s shadowy southern rebellion has left more than 6,500 people dead since it erupted in 2004. But the violence rarely makes international headlines or affects Thais outside the conflict zone, a Muslim-majority region annexed more than a century ago. Analysts say the rebels are frustrated over stalled negotiations with the military government. “It looks like the work of (the insurgents), judging from their kind of arms… it was not aimed to create mass casualties, so that’s very similar to the far south,” Don Pathan, a security analyst and expert on the insurgency, said of last week’s bombings. But he said the junta would be loath to admit a major expansion of the conflict, since it would signal a significant “policy failure in the south”. A leader of the “Red Shirts” — the grassroots movement supportive of the ousted government and hostile to the junta — expressed concern Sunday his network would be fingered for the attacks. “We have been made victims for things we did not do several times before,” Jatuporn Prompan said in a video posted on Facebook. The Red Shirts, who hail chiefly from the poor and rural northeast, are fiercely loyal to the powerful Shinawatra family, whose repeated election victories have been undone by two coups and a series of judicial rulings in the past decade. Their political network has come under heavy surveillance by the military since the 2014 coup. The bombings in top tourist destinations, including the island of Phuket, threaten a vital source of income for tropical Thailand. The sector accounts for at least 10 percent of an economy the military government has struggled to revive.