BANGKOK -- Two migrant workers from Myanmar convicted in the 2014 killings of two young British tourists on a Thai holiday island have had their death sentences reduced to life imprisonment.

Zaw Lin and Wai Phyo were among many convicts in Thai prisons whose sentences were reduced under a clemency decree issued by King Maha Vajiralongkorn to mark his 68th birthday on July 28, their lawyer, Nadthasiri Bergman, confirmed. The decree, which appeared to cover thousands of prisoners, took effect Friday with its publication in the Royal Gazette.

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 diving destination.

The high-profile case caused extensive controversy because of allegations police mishandled evidence and beat the suspects into making confessions. There were suspicions they were scapegoats for a crime that police were under pressure to solve because it could adversely affect Thailand's lucrative tourist industry.

A well-known Thai forensics expert testified that the DNA evidence that was central in the prosecution case did not link them to the scene. Human Rights Watch called the guilty verdict "profoundly disturbing."

The Supreme Court in August last year upheld their murder convictions and sentences. It dismissed allegations of physical mistreatment and mishandling of forensic evidence, saying the forensic work was handled by respectable institutions and it found no proof of torture.

The death penalty is rarely carried out in Thailand.