Lawyers for two men charged with the murder of a pair of British tourists - including Jerseyman David Miller - in Thailand are "deeply concerned" that key forensic evidence will not be re-examined before the trial.
Hannah Witheridge (23), from Norfolk, and Mr Miller (24) were killed on the island of Koh Tao last September.
Migrants Zaw Lin and Win Zaw Htun, both 21-year-old bar workers from Burma, are set to stand trial on 8 July on charges of murder and rape.
Their defence lawyers have asked for forensic evidence gathered by Thai police to be sent to independent experts but the judge in the case has said that he will not rule on the matter until the first day of the trial.
Lead lawyer Nakhon Chomphuchat told the BBC: "I am now deeply concerned at this developing situation.
"Without re-examination of this evidence by the Ministry of Justice's Central Institute of Forensic Science, the ability of the two defendants to defend themselves against the serious crimes they are charged of will be seriously impeded."
The investigation into the deaths of the young Britons has been marred by confusion and allegations of police incompetence.
The defendants are said to have confessed under pressure from local police shortly after the killings but have since retracted those statements.
Both of the victims' families have previously said they are keen to see the "right people" convicted.
The Witheridge family recently announced they had raised enough money to attend the trial through an internet appeal.
Writing online, Miss Witheridge's sister Laura said: "The past six months have been indescribably horrific, I would never be able to expose the hell that our family has endured."
Comments on this story express the views of the commentator only, not Bailiwick Publishing. We are unable to guarantee the accuracy of any of those comments.
Once your comment has been submitted, it won’t appear immediately. There is no need to submit it more than once. Comments are published at the discretion of Bailiwick Publishing, and will include your username.