Thailand backpackers murder trial: Police fail to present key evidence over deaths of Hannah Witheridge and David Miller

Defence lawyers say omission of key forensic evidence casts doubt on fairness of murder trial of two Burmese migrant workers in Thailand

Myanmar migrant workers Zaw Lin, center, and Win Zaw Htun, rear, arrive at a provincial court in Surat Thani province, Thailand (AP)

Key forensic evidence "may have been destroyed" in the trial of the Burmese workers accused of killing two British backpackers in Thailand.

On the second day of the three-month trial in a Thai court, Police Lieutenant Colonel Somsak Nurod presented a list of exhibits related to the case, including a garden hoe – the alleged murder weapon, but failed to present crucial DNA evidence, according to the BBC.

The DNA samples, taken from sperm and a cigarette at the scene, may have been used up in testing or lost, it has been reported.

Burmese migrants Zaw Lin and Wai Phyo, both 22, are on trial for the murders of 24-year-old David Miller, from Jersey, and 23-year-old Hannah Witheridge, from Norfolk.

Having previously confessed to police, the accused have denied the charges.

David Miller, 24, and Hannah Witheridge, 23 were killed on the small island of Koh Tao

The first police officer to reach the scene has given evidence, describing how the bodies, mostly unclothed, were found a few metres apart and showing signs of a brutal attack.

According to human rights groups, Burmese migrant workers have been wrongly accused of crimes by Thai police in the past.

Lead defence lawyer Nakhon Chompuchat said that police will confirm later today what evidence they have, and that the defence team had "expected" that the DNA evidence could be missing or unusable.

The news that key DNA evidence may have been lost draws further criticism on the investigation which has already suffered allegations of police misconduct against witnesses and improperly collecting evidence. The allegations have been denied by Thai police.

Thai authorities have been under pressure to resolve the case quickly as the death of tourists threatens the country’s vital tourism industry.

The father (left) and brother of murdered British backpacker Hannah Witheridge, leave Koh Samui court in Thailand on 8 July (Jerome Taylor/AFP/Getty Images)

Met police were sent to Thailand last year to review the case and report back to UK authorities and the families of the victims.

The Miller family said in a statement this week: "The act which ended David’s life devastated our family and his friends."

"Over the coming weeks we hope to gain a better understanding as to how such a wonderful young man lost his life in such idyllic surroundings in such a horrible way," a family spokesperson said.