Semen found on the body of one of the two British tourists murdered on Thailand's Koh Tao island a week ago will be examined in a Singapore laboratory, a Bangkok newspaper reported.
The DNA test would be able to identify the race of the attackers, which would help in the investigation, it quoted the Thai national police chief as saying.
General Somyot Poompanmoung said the police were trying to pinpoint how long the attackers were at the scene based on cigarette butts left there.
The police had found, through DNA analysis, that one of the cigarettes was smoked by two people, and semen from both men was found in the female victim's body, The Nation reported.
But it did not match any DNA records, the UK's Daily Mirror reported.
Surveillance camera footage of all travellers coming to the island and leaving it was being examined.
DNA samples had been collected from 12 suspects and another 30 people were potential suspects in the killing of Ms Hannah Witheridge and Mr David Miller, both aged 24.
This article was first published on Sep 22, 2014.
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