Details about Bill Mah have emerged after his friend Ken Fraser raised questions about his death.
Mr Mah wasn't staying at the Downtown Inn, but Mr Fraser said the 59-year-old had used the hotel's facilities, including the swimming pool, for which coupons were available in his own hotel.
Mr Mah had been in Chiang Mai for two weeks before falling ill at a dinner party on January 24. The next morning, he complained of lack of sleep because of chest pains and was taken to hospital, where tests ruled out a heart attack.
He was sent home two days later with medication for acid reflux but was found dead in his room that night.
Mr Fraser said his friend had only just retired from work after having gone 25 years without missing a single day through illness.
A report states "suspected natural disease pending lab reports and toxicology" as the cause of death, but Mr Fraser said those results and the official cause of death had not been released. "I know Bill used the facilities at the Downtown Inn because he asked me to go there with him but I had other things to do. What natural disease are they saying he had?"
Mr Mah's friends and relatives are now joining a chorus of people who believe Thai authorities are playing down the presence of a virus.
Ms Carter's father, Richard Carter, believes there is a cover-up. He has called for the Downtown Inn to be closed until the truth is uncovered and would like to see an independent investigation into the deaths.
The manager of the Downtown Inn was not available for comment.
The Herald understands an initial swab result has suggested Ms Carter had contracted echovirus. The disease is linked to dirty and overcrowded conditions but Thai police have given the all-clear to the Downtown Inn.
Thailand's Department for Disease Control said it could not find links between the deaths or a link to the Downtown Inn, which is owned by a former mayor of the city.
GROWING TOLL IN CHIANG MAI
* Jan 11: American Mariam Soraya Vorster, 33, staying at a different hotel, but dies from swelling of the heart.
* Jan 26: Canadian Bill Mah, 59, dies after using the facilities of the Downtown Inn.
* Jan 9-Feb 4: A French woman died during this period from swelling of the heart.
* Feb 3: Thai tourist guide Waraporn Pungmahisiranon, 47, dies in the Downtown Inn.
* Feb 4: Kiwi Sarah Carter, 23, taken from Downtown Inn to hospital. She died two days later, also with swelling of the heart.
* Feb 18: British couple George and Eileen Everitt, who are in their 70s, both die from heart attacks at the Downtown Inn.