Mystery surrounds the deaths of two Americans during what was meant to be a dream vacation in paradise in Fiji. 

Texas couple David and Michelle Paul fell ill with flu-like symptoms after arriving in Fiji two weeks ago. Michelle died three days later. Her husband later lost his life as preparations were being made to medevac him to Australia.  

David was an Air Force veteran and Michelle was a former college athlete. 

“These are two extremely healthy individuals,” Tracey Calanog, Michelle's sister-in-law, told Inside Edition. “They're pretty sure it was some kind of virus that was in something that that they ate or drank, something like that."

One theory is that David and Michelle died from a severe strain of flu that has been sweeping the South Pacific. The World Health Organization has been warning travelers about a flu virus that targets people in the prime of their lives, their 20s and early 30s.  

Now, 15 people at the resort in Fiji where the couple were staying are being monitored for similar symptoms. 

The couple was married three years ago in Hawaii. They have a 2-year-old son named Aden, and David has a daughter and two sons from a previous relationship.  

Michelle's father spoke out on the “Today” show Tuesday. 

“Nobody is telling me what was the cause of the death and that's very hard for me,” he said. “My wife, she cries very hard but I keep telling my wife that we've got to stay strong because we have a new job — Aden. We have to take care of Aden.”

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