Myanmar investigators say the two migrant workers accused of murdering two British tourists in Thailand are innocent.

They say some Myanmar nationals they've spoken to on Koh Tao island could provide evidence but they're reluctant to testify.

(SOUNDBITE) (Burmese) INVESTIGATOR OF THE MYANMAR INVESTIGATIVE COMMITTEE, KYAW THAUNG, SAYING;

"If the witnesses say what they know, they will lose their job. They are afraid of the Thai police and the Thai bosses. That's the main difficulty for us."

The bodies of David Miller and Hannah Witheridge were found on a beach in September.

Zaw Lin and Win Phyo were arrested after police said their DNA matches samples found on the victims.

Both initially confessed to the killings but then said the admissions were made under duress.