- Police say DNA test don't match evidence from female victim's body
- DNA was taken from two British brothers and 11 other men
- Autopsy: Slain woman had signs of sexual intercourse, getting hit in head
- The male victim had water in his lungs, was hit by hard object, police say
Thai police are still searching for suspects in the killings of two British tourists on an idyllic resort island after DNA tests on more than a dozen men found no matches with evidence from the female victim's body.
Provincial police chief Kiatthipong Khaosumarng said that experts carried out the tests on DNA samples from 11 migrants working on the island and two British brothers, one of whom had shared a room with the male victim.
No one has been arrested yet over the killings on the island of Koh Tao, nor has anyone been officially named a suspect. Police had previously asked the two British brothers, Christopher and James Ware, not to leave Thailand, saying they were "under watch."
Kiatthipong declined to comment on reports that the two brothers have now been allowed to leave Thailand.
Police are now trying to find other people who were caught on surveillance video the night the two tourists -- Hannah Witheridge, 23 and David Miller, 24 -- were killed, he said.
An autopsy revealed both victims had been hit by a hard object, according to Maj. Gen. Pornchai Suteerakhun, the head of the Police Hospital's Institute of Forensic Medicine.
Miller was hit and had scratches on his back, in addition to having water in his lungs consistent with drowning, an autopsy showed. Witheridge was hit several times on her head and face and her body had evidence of sexual intercourse, according to her autopsy.
Pornchai didn't confirm or deny that authorities believe Witheridge was raped.
Kiatthipong said that two sets of DNA have been found on Witheridge's body, indicating at least two culprits in her death. Neither set matches that of Miller, he said.