BANGKOK - Thai police Tuesday ruled out three Myanmar workers in connection with the murder of two young British tourists, as Thailand's military ruler appeared to call into question the "behaviour" of the victims themselves.
The bodies of David Miller, 24, and Hannah Witheridge, 23, arrived in Bangkok late Tuesday for forensic examination.
They were found naked and beaten to death early Monday near a beachside bungalow on the island, a diving hot-spot near Koh Phangan in the Gulf of Thailand.
A bloodied hoe was discovered 35 metres (yards) from the murder scene.
Three male Myanmar migrant workers were held for questioning but ruled out of the probe on Tuesday afternoon, southern regional police commander Panya Maman told AFP.
"They were very far from the scene... it was probably not them," he said, adding DNA samples had been collected from the men.
He did not give details of any further leads as the manhunt on the small, normally tranquil island stretched into a second day without an arrest.
Police have also cleared a number of British tourists who travelled with the victims of any involvement in the killings.
Earlier Tuesday local television showed Thai authorities searching several shacks belonging to Myanmar migrants on Koh Tao. Migrants from Myanmar and Cambodia are frequently accused of committing crimes in the kingdom, where they make up a vast, poorly-paid and low-status workforce.
'Affected our image'
On Tuesday Thai junta chief and prime minister Prayut Chan-O-Cha appeared to call into question the victims' conduct in addition to the perpetrators of the attack.
"We have to look into the behaviour of the other party too because this kind of incident should not happen to anybody and it has affected our image," he told reporters, referring to the two tourists.
Thai authorities were working "swiftly" to find the killers, he added.
Koh Tao, home to stunning white sand beaches and azure waters, is popular with divers but is smaller and more laid-back than neighbouring Koh Phangan - which draws hordes of backpackers to its hedonistic "full moon" party.
Speaking later Prayut said Thais must tell "tourists when the safe times are to be outside, we have to help them understand."
Police earlier said the pair had been seen partying at a local bar just hours before they died.
Thailand will be desperate to avoid further damage to the nation's lucrative tourism industry, which has been battered in recent months after a prolonged political crisis ended in a coup.
The army swiftly blanketed the country with a curfew and strict martial law, frightening off visitors. Although the curfew was soon lifted from key tourist hotspots, visitor numbers have yet to rebound and martial law remains in place.
Military leaders have vowed to restore the nation's reputation as the "Land of Smiles" with a clean-up targeting tourist resorts after a series of complaints about scams, assaults and even police extortion.
Britain says Thailand is the country where its citizens are second most likely to require consular assistance if they visit, behind the Philippines.
There were 389 deaths of British nationals in Thailand in the year to March 2013 - about one for every 2,400 British visitors or residents - although that figure includes natural causes.
But it is rare for tourists to be murdered in Thailand, although it is not uncommon for visitors to die accidentally.