Two Burmese men suspected of murdering British backpackers Hannah Witheridge and David Miller are set to face trial in Thailand as the victims' families arrived in the Southeast Asian nation.
The two were murdered in Thailand in September 2014 and their bodies were found in a beach resort on the holiday island of Koh Tao.
Witheridge, 23, from Norfolk was found to have been raped and beaten. Miller, 24, from Jersey was thought to have suffered head injuries before he drowned in the sea.
The suspects, Zaw Lin and Wai Phyo, both aged 22, have denied the murder charges as the families seek justice. The Burmese pair had initially confessed to murders when they were arrested two weeks after the incident but later claimed they admitted to the crimes under duress.
The prosecutors will present their witnesses for 12 days at the hearing. The trial could take up to October.
Miller's family said in a statement: "The act which ended David's life devastated our family and his friends. Just hours before he died, David was talking to us with his usual enthusiasm, describing the beauty of Koh Tao and the friendliness of the Thai people."
"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."
Police have argued the DNA evidence collected from the murder scene match the two Burmese. But the defendants' legal team has sought an independent re-examination.
Nakhon Chompuchat, chief lawyer for the suspects, said: "We are convinced our clients were tortured to confess to the murders, and if the government grasps the issue and brings some clarity to it, it will end credibility to the government. But if the court eventually finds that they were tortured, the credibility of the will be damaged."
Ko Sein Htay, president of the Migrant Workers Right Network who is working on behalf of the defendents, said: "A fair trial for Zaw Lin and Wai Phyo is essential to ensure, with more confidence, that those guilty of this crime are held accountable and that there is no punishment of the wrong people."