The mothers of Zaw Lin and Wai Phyo, accompanied by other relatives, lawyers and a senior diplomat from Myanmar's Embassy in Thailand, submitted an official petition for clemency Thursday at Bang Kwang prison on the outskirts of Bangkok, where the two men are being held.
The two denied killing 24-year-old David Miller and raping and killing 23-year-old Hannah Witheridge, whose battered bodies were found on a beach on the island of Koh Tao in the Gulf of Thailand, a popular destination for diving.
The verdicts were controversial because of allegations police mishandled evidence and beat the suspects into making confessions. A well-known Thai forensics expert testified that the DNA evidence that was a central plank in the prosecution case did not link them to the scene. Human Rights Watch called the verdict "profoundly disturbing."
Dressed in traditional Myanmar clothing, the two mothers — May Thein and Phyu Shwe Nu — said they hoped King Maha Vajiralongkorn would grant their plea and reduce their punishment to life imprisonment.
"We believe our sons are innocent," said May Thein, mother of Wai Phyo. "Many people believe the same thing as us." Zaw Lin and Wai Phyo were arrested shortly after the killings. They were employed as service workers on the island.
The case strained relations between Thailand and Myanmar, with several demonstrations in Myanmar denouncing the proceedings. At the end of August, the two men exhausted their appeals when the Supreme Court upheld their conviction.
The death penalty is rarely carried out in Thailand but in June last year, the country carried out its first execution in nine years by lethal injection.