Krabi police are struggling to find clues about the mysterious death of two Canadian sisters at their hotel room on Koh Phi Phi.
Sisters Noemi, 20, (left) and Audrey Belanger, 26, in copies of their passport photos. (Provided by Royal Thai Police)
The tourists' corpses will be sent for further autopsies at a better-equipped hospital in Songkhla or Bangkok.
Muang Krabi police chief Thaksin Pochakorn said there were no signs of a struggle in their rooms or on their bodies, and investigators were looking for other possible causes of the deaths.
"We are waiting for the post-mortem examination of the victims' inner organs to see if there are any traces of toxic substances," Pol Col Thaksin said.
The bodies of Noemi Belanger, 26 and Audrey Belanger, 20, were found in their hotel room on Koh Phi Phi off Krabi province on Friday.
The holidaying sisters checked in at Phi Phi Palms Residence in tambon Ao Nang of Muang district last Tuesday.
Witnesses said the women went out and returned to the room late at night and did not come out in the morning.
Concerned hotel staff used a master key to enter the ground-floor room.
Police said large amounts of vomit were found in the room and the women had bleeding gums and bleeding under the skin. Their nails appeared to be blackened.
Krabi hospital director Komgrib Phukittayakamee said Sunday the women's bodies, which were being kept at his hospital, will be sent for a post-mortem examination at either the Police General Hospital in Bangkok or at Songklanagarind Hospital.
Dr Komgrib said he and Phi Phi hospital director Duangporn Paothong had jointly examined the dead bodies of the tourists and found they had suffered no physical injuries. It was too soon to pinpoint the cause of the deaths, he said, adding that bleeding gums and bleeding under the skin were not always linked to poisoning.
Such symptoms are usually found on diseased people, the doctor said.
Canadian embassy officials had arrived at the hospital to talk to the authorities about the pathology tests, he said.
Dr Komgrib said health authorities would not issue any health advisory to tourists and residents until they received more information from the autopsy and pathology testing results, expected in the next few days.
Phi Phi Palms Residence, where the women stayed, opened in 2009.
The two-storey lodging is about a two-minute walk from the famous Loh Dalum beach on the island.
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