Amnesty International has called for an investigation into claims two men accused of killing British tourists in Thailand have been tortured by police.
The Burmese workers have been charged with the murder and rape of Hannah Witheridge, 23, from Great Yarmouth, and killing 24-year-old David Miller, from Jersey, on the Island of Koh Tao last month.
Last week, they were paraded by police at a news conference which included a re-enactment of the attacks on the beach where the Britons' bodies were found.
Now Amnesty International said a lawyer, from the Burmese embassy legal team who is acting for the accused, had been told by one of the men that officers had beaten him and "threatened him with electrocution".
The human rights charity has called for an investigation.
The Thai authorities must initiate an independent, effective and transparent investigation into mounting allegations of torture and other ill-treatment by police.
The pressure to be seen to be solving an appalling crime that has garnered considerable attention should not result in the violation of rights, including to a fair trial.
Thai police deny the allegations.
Two Burmese workers, who have confessed to the killing of British tourists on the Thai island of Koh Tao, have been paraded by police.
The pair, whose names were given only as Saw and Win, were taken to the island as police carried out a reconstruction of the night David Miller, 24, and Hannah Witheridge, 23, were brutally killed.
General Somyot Poompanmoung, Thailand's national police chief, said they both face charges of murder, rape and theft.
He added that DNA results, CCTV footage and other evidence supported the men's confessions that they raped and killed Ms Witheridge and murdered Mr Miller.
DNA samples taken from the body of murdered British tourist Hannah Witheridge has matched those of two Burmese men in police custody in Thailand, police said.
Thai National police chief Somyot Poompanmoung also told the AFP news agency that the two suspects had admitting killing Hannah, 23, and her friend David Miller, 24, on Koh Tao island last month.
DNA test results [from the two suspects] confirmed that same DNA was present that we found in body of the [female] victim.
Police are now waiting for a local court to issue a warrant so that the men can be formally charged.
Two Burmese immigrant workers have confessed to killing two young British tourists on a Thai holiday island last month, police have said.
Major General Kiattipong Khawsamang said that two of three Burmese workers questioned by police admitted murdering the couple.
He said the other man has denied involvement. Police have previously said they believe three people were involved in the attacks.
A Burmese man has confessed to the murder of two British tourists in Thailand, according to Reuters news agency.
The island were the pair were killed has a large community of migrant workers from neighbouring Burma.
The investigation has advanced considerably.
Three Burmese workers were detained and we took their DNA for testing. During the investigation one of them admitted to killing the two foreigners.
Jaktip told Reuters that the man who had confessed was being detained but had not been arrested.
"We still have to wait for DNA tests results which we expect to have in 14 hours from now in order to confirm this," he said.
The bodies of Hannah Witheridge, 23, and David Miller, 24, were found on Sept. 15 with severe head wounds near where they were staying on the southern island of Koh Tao, known for its coral reefs and diving.
Tourists in Thailand may soon have to wear identification wristbands, the country's tourism minister has claimed, amid ongoing concerns over tourist safety.
It follows the murder of British tourists Hannah Witheridge and David Miller earlier this month.
Kobkarn Wattanavrangkul said she had approached hotels with the idea of using wristbands to help identify tourists lost or in trouble.
"When tourists check-in to a hotel they will be given a wristband with a serial number that matches their ID and shows the contact details of the resort they are staying in so that if they're out partying late and, for example, get drunk or lost, they can be easily assisted," Kobkarn told Reuters.
She said "electronic tagging" may be the next step, while plans to use a "buddy system" - pairing tourists with a local minder - was also being discussed.
Police in Thailand are offering a reward of more than £13,000 in their bid to catch the killers of two British tourists.
The bodies of David Miller, 24, and Hannah Witheridge, 23, were discovered on a beach on the tiny island of Koh Tao on September 15.
A bloodstained garden hoe, believed to be the murder weapon, was found nearby.
A group of Thai footballers are the latest people to be questioned by police amid fears that the hunt for the killers has stalled.
A spokesman for the Royal Thai Police confirmed that DNA samples were taken from "more than eight" footballers - who reportedly threw a late-night party at the nightclub where the victims spent their final hours - and officers were awaiting the results.
Police in Thailand say they have "fresh evidence" that two British backpackers may have been murdered out of "sexual jealousy".
David Miller, 24, and Hannah Witheridge, 23, were found dead on the island of Koh Tao last Monday.
Police Colonel Kissana Phathanacharoen said: "We have discovered fresh evidence which could lead to a new suspect who may have had a relationship or one night stand with Hannah or one of her friends or David the night before they were killed."
"We have asked the Metropolitan Police to go back and make enquiries of Hannah's friends on this matter"
He added that police could not confirm reports that David and Hannah had had a fight with a Thai man in a bar the evening they died.
The father of the British man murdered in Thailand believes his son had stepped in to help his fellow victim when they were both brutally killed on an island.
Ian Miller said it was in his 24-year-old son David's character to help, and claimed that was probably the circumstance when he and Hannah Witheridge were murdered in Koh Tao a week ago.
He told the Daily Mail: "It has become clearer and clearer that it is quite likely David was stepping in to help a girl who was in trouble.
"That would be absolutely in his character."
The family Hannah Witheridge said they have brought the body of the British holidaymaker who was brutally murdered together with a fellow tourist in Thailand back to the UK
Hannah 23, was found with severe head wounds next to David Miller, 24, on a beach on the island of Koh Tao on Monday.
We can confirm that we have now returned to the UK with our beautiful Hannah.
As a family we feel enormous relief to have Hannah back at home where she belongs.
We continue to work closely with officers to assist in the investigation and bring those responsible to justice.
Our family is broken and require time to grieve in private - as do Hannah's many friends. With the support of our fantastic family liaison officers we will make further statements as required and when we feel able.
As such, we would be very grateful for time and privacy to try and come to terms with our devastating news.
Her family said today that they had travelled to Bangkok on Tuesday to bring their "beloved Hannah" home and find out more about the investigation.