I was listening to radio 2 today and they were talking about a young NZ woman who died suddenly at the Downtown Inn Hotel in Chiang Mai, her two friends also nearly died, the NZ girl's father has set up a website to advise travellers of the danger posed to tourists, www.thailandtraveltragedies.com.
It turns out that his daughter was not the only person to have died at this hotel, 6 others including an elderly British couple have died since Jan 2011. It is suspected that the hotel water could hold the key, as one expert on radio 2 said that this was definitely not a case of food poisoning, something far more toxic would have caused the NZ girl's death. Reading the posts on the website it seems Thailand is a dangerous place for tourists and deaths are very common, but never solved.