Fresh agony for families of two British backpackers in their 20s bludgeoned to death in Thailand 10 years ago after two convicted killers demand review of case as they plead their innocence

The families of two young backpackers who were bludgeoned to death 10 years ago face fresh agony after two convicted killers have demanded a review of the case.

Zaw Lin and Win Zaw Htun, both 29, were originally sentenced to death for the murder of David Miller and the murder and rape of Hannah Witheridge but a Thai royal decree changed their sentences to life in prison.

The bodies of David and Hannah - aged 24 and 23 at the time - were discovered on a beach on the popular tourist island of Koh Tao in September 2014.

But the Burmese bar workers who were convicted 10 years ago are still maintaining their innocence - and are demanding a review of the case.

They claim they were stitched up and accused detectives of carrying out a 'botched' investigation, The Mirror reported.

In letters seen by the newspaper, Zaw Lin told his legal time he has been in prison all this time 'for nothing, it's unbelievable' and said: 'Could you please retrial again my case? I’ve never seen the people who died on the beach at Koh Tao.'

This claim will likely bring fresh pain for the victims' families as letters sent from the notorious Bang Kwang jail from Lin said: 'I want to get out as I am innocent'.

In another letter, he said he has wasted his 'young life' in prison for 'nothing' as he turns 29.

He added that he will 'get out' of prison in a 'few years' as he has been imprisoned for a 'long time'.

The trial in Koh Samui heard that a garden hoe was used to beat the two young victims. Lin claimed in his letters that the forensic evidence linking him to the tool was flawed.

In January, the killers' legal representatives contacted the authorities to ask for 'clarity' on their efforts to reduce their time in prison - but they were told this would not change. 

The convictions were mired in controversy with supporters of the two men arguing that they had been framed and that they had initially confessed to the crimes under duress.

In 2019, Zaw Lin and Win Zaw Htun's mothers submitted a plea for clemency from the Thai king in a case tainted by claims of irregularities - saying the confessions by the pair were obtained under duress.

Their defence lawyers have also said the evidence used to convict the two men was unreliable as authorities had mishandled DNA and did not allow independent analysis of the samples.

When Thailand's King decreed the killers wouldn't be executed, the victims' parents welcomed the royal pardon.

David Miller's parents, Ian and Sue Miller, said they were 'grateful' to Thai King Maha Vajiralongkorn for reviewing the sentences.

The couple have previously campaigned against the death penalty.

In a statement they said: 'We are grateful to His Majesty the King of Thailand for showing his clemency to the murderers of our son David.'

But they added that they hopes the killers would spend a 'very long time in jail where they cannot harm other families'.

The two men were convicted and sentenced in 2015 and the verdict was upheld by an appeals court in 2017 and the Supreme Court in August 2019 but their sentences were changed to life in prison thanks to a royal decree.

'I can't find words to express how thankful we are,' Ye Zaw Tun, a brother of Win Zaw Tun, told AFP following the decree.

'We knew this case was totally unfair, and we sometimes feel bitterness, but we want to say thanks for the royal pardon.'

Ms Witheridge, a University of Essex student from Hemsby, Norfolk, and Mr Miller, of Jersey, who had just completed a civil and structural engineering degree at the University of Leeds, met on Koh Tao while staying at the same hotel.

A cleaner heading home in the early hours came across their battered bodies on Sairee Beach.

Ms Witheridge had been savagely raped and beaten to death and Mr Miller had been beaten unconscious and left to drown in the incoming tide.

Police recovered the murder weapon - a short-handled garden hoe - from a small garden bed nearby.

Following their murders, many in Thailand felt the two men accused of killing them had been given an unfair trial as low-paid migrant workers - an integral part of Thailand's workforce - are often regarded with contempt by its public.

Prosecutors said DNA evidence collected from cigarette butts, a condom and the bodies of the victims links the two suspects to the killings.

But lawyers representing the two men said DNA samples from the alleged murder weapon - a garden hoe - did not match that of the two suspects.

The defence team also claimed DNA evidence was mishandled by police and the defendants' confessions were a result of 'torture or abuse that made them fear for their lives' in the context of 'systematic abuse' of migrants on Koh Tao.

The men told the court that they had had plastic bags placed over their heads so they couldn't breathe, were physically beaten and were threatened with being killed and their bodies dumped in the sea.

A bizarre re-enactment of the murders in which the suspects were paraded in front of the media was also 'staged under threat of violence', the lawyers added.

Thai police denied using force during their investigation.

After their initial sentences in 2015, Mr Miller's father Ian, mother Sue and brother Michael who attended the court hearing, spoke after the judges delivered their verdicts.

On the steps of the court, his brother said: 'We believe the result today was justice for David and Hannah.

'David always stood up for justice and justice is what was delivered today.

'We didn't know what to believe. It was easy to conclude they might be scapegoats. We heard the evidence and a group of activists has promoted their cause to the media.

'They had seven top lawyers and ultimately they obtained the best possible representation in court.

'We have attended the trial and gained respect for the court. We came to realise the police investigation was not the shambles it was made out to be.

'It is our opinion that the evidence against Zaw Lin and Wai Phyo is absolutely overwhelming.'

Following the murders, Koh Tao earned the nicknamed of 'death island' due to the number of western tourists who had died or gone missing there.