An investigation into the mysterious deaths of five foreign tourists, including an elderly couple from Lincolnshire, in hotels in northern Thailand suggests a link to toxic chemical exposure but has failed to determine exactly what killed them, according to a government website.
George Everitt, 78, and his wife Eileen, 73, from Boston, Lincolnshire, were found dead in their room at the Downtown Inn in Chiang Mai.
The other victims were tourists from New Zealand, France and the United States who were staying at three different hotels in the popular northern Thai city. A Thai tour guide also died, and three other tourists also fell ill but recovered.
No-one has been declared responsible over the spate of deaths, which happened in January and February.
"The specific agents that caused the deaths and illnesses in these events cannot be identified, and it cannot be determined exactly how people were exposed to them," the Department of Disease Control said on its website.
The results were most revealing concerning a 23-year-old New Zealand woman who died on February 6, her two female companions, both also 23, who fell ill but recovered, and a 47-year-old Thai woman who died on February 3.
The four are "most likely to have the same cause of illness - probably exposure to some toxic chemical, pesticides or gas", the report stated.
The deaths of the British couple who were found in their hotel room on February 19 were "possibly related" to the those deaths "as they occurred in the same hotel", the report added. The hotel owner has declined to comment.
In the case of the 33-year-old American woman who died on January 11, "the suspected agent that caused her death is likely to be chemical or biotoxin in nature and it is probable that it might have been a pesticide", the report said. She was staying in a different hotel in the same area, and a 29-year-old Canadian woman travelling with her fell ill but recovered.
The final victim, a 25-year-old French woman who died on January 19, the report states "developed fever and other symptoms on 16 January before arriving in Chiang Mai" so her case is probably not related to the others.