Thai authorities will meet today to discuss the possibility that New Zealander Sarah Carter was killed after being exposed to high levels of a chemical used to kill bed bugs.
Dr Pasakorn Akarasewi from Thailand's Ministry of Public Health told the Herald a video conference would be held between the Chiang Mai investigation team and health experts in Bangkok.
"They will discuss the overall [investigation], but also the possibility of the report in New Zealand about pesticides."
He said it would be decided in the meeting whether new swabs would be taken from the Downtown Inn to test for traces of the toxin chlorpyrifos.
In February, Ms Carter died in hospital from heart inflammation two days after she and two friends became sick while staying at the Downtown Inn.
Seven people have died in similar circumstances to Ms Carter - including an elderly British couple and a Thai woman who stayed at the Downtown Inn, and a Canadian man who used the hotel's facilities.
Late last month TV3's 60 Minutes travelled to Thailand and secretly took swabs from the room in which Ms Carter stayed.
New Zealand scientist Dr Ron McDowall, who specialises in hazardous chemicals, has said analysis of the swabs indicated a strong likelihood Ms Carter's death was caused by exposure to the insecticide.
A number of laboratory tests - some in the United States and Japan - are still continuing on the victims' bodies, food and environment.
They have been carried out with the help of the World Health Organisation, who previously told the Herald "all possibilities are being considered, including something infectious or toxic".
A spokesman for the WHO's Thai office said yesterday that the organisation had offered to provide access to international toxicologists, but the investigation remained Thai-led.
Dr Akarasewi said today's meeting would hear from experts on whether the pesticide could have solely caused Ms Carter's death, or "weakened her".
But her father, Richard Carter, said he was all but convinced by Dr McDowall's findings and had personally contacted a senior Thai health official who agreed to take further swabs.
"We just need to make sure that we're 100 per cent sure of everything ... and that would probably give more authority to have something done about it within Thailand."
Mr Carter said today's meeting did not necessarily indicate the authorities were taking the case seriously.
"Hopefully it's not a meeting to work out how they're going to do a further cover-up.
"I just hope they adopt an attitude of looking towards the long term and getting this out in the open."
The chlorpyrifos revelation had provided some closure, he said, but nothing would bring Sarah back.