Bangkok - DNA from a Briton questioned over the murder of two countrymen on a Thai beach this week did not match evidence found on the female victim, police said on Thursday.
The man had been travelling with them, and was questioned twice by police this week, the second time as a suspect on Wednesday, before being released.
“The DNA results of the semen do not match that of the friend,” Police Sergeant Apichet Cherdguea told reporters.
“We have to start looking at the case again,” he said.
DNA from two men were found on the woman's body, said Major General Giattipongn Kaosum-ang, the commander of the local police district.
“The DNA results don't match that of the travelling companion, or the migrant workers we had called in earlier.”
The bodies of the tourists were found on the beach on Monday at the island resort of Koh Tao, 350km south of Bangkok.
The couple, both 24, suffered extensive injuries to the head and neck.
In the past five years, 13 British tourists have been murdered in Thailand, out of the more than four million who visited the country. - Sapa-dpa