KOH SAMUI, Thailand (Reuters) - - A Thai court sentenced two Myanmar migrant workers to death on Thursday after convicting them of the 2014 murders of two young British tourists on a holiday island in a case mired in controversy and a dispute over DNA testing.

The battered bodies of backpackers Hannah Witheridge and David Miller were found on a beach on the island of Koh Tao in September 2014. Police said Witheridge, 23, had been raped and bludgeoned to death and Miller, 24, suffered blows to his head.

Following pressure to solve the case, police arrested Myanmar migrant workers Zaw Lin and Win Zaw Tun and said the two had confessed to the crimes. Both later retracted their confessions, saying they had been made under duress.

The brutality of the murders dented Thailand’s image as a happy-go-lucky holiday paradise and raised serious questions about its treatment of migrant workers.

The verdicts on Samui island, close to Koh Tao, follow an investigation that triggered allegations of police incompetence, mishandling of evidence and DNA tests and torture of the suspects.

Thursday’s ruling caused outrage in Myanmar and dozens of police were deployed to guard the Thai embassy in Yangon amid calls on social media for a protest. About 10 people stood outside the building holding placards demanding their release.

Myanmar Facebook user Myo Phont described the outcome as “entirely predictable”.

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“Poor boys - wrong time, wrong place ...the Burmese are the scapegoats as usual.”

A Facebook user named Thiri posted: “Is it real? What the hell? DNA doesn’t match and still death sentence?”

As is customary in Thailand, where trials have no jury, a judge delivered the ruling and said DNA tests were carried out to acceptable standards and samples found on Witheridge’s body matched that of the defendants. The judge also said the claim of police torture carried no weight.

The debate over DNA samples that police say linked the two suspects to Witheridge was core to the trial.

Defence lawyers had asked to retest DNA samples but authorities issued conflicting statements on that evidence and, at one point, said DNA had been used up. No independent re-testing was done.

“PAINFUL AND CONFUSING INFORMATION”

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Miller’s family attended the verdict and brother Michael delivered a statement to reporters saying justice had been served, adding the two men had shown no remorse.

“We believe what happened today represents justice for Hannah and David,” said Miller. “The Royal Thai Police conducted a thorough and methodical investigation ... evidence against the two was overwhelming.”

Witheridge’s family said the trial had been distressing.

“We found listening to proceedings very challenging and we have had to endure a lot of painful and confusing information,” the family said in a statement.

“We now need time, as a family, to digest the outcome of the trial and figure out the most appropriate way to tell our story.”

The mother of one of the defendants broke down in tears as the judge passed sentence. Defence lawyer Nakhon Chompuchat said an appeal would be filed within a month.

Police were widely accused of bungling the investigation, including failing to close off the island quickly and allowing potential suspects to escape.

Zaw Htay, a senior president’s office official, said Myanmar would explore all legal and diplomatic means and “leave no stone unturned” to secure the release of “two innocent men”.