A young Texas couple mysteriously died of an illness while on an “amazing vacation” in Fiji, ABC News reports. Officials on Fiji’s main island called to inform family members of David and Michelle Paul’s sudden death, but when and how they died remains unclear. “We offer our sincerest condolences to the family on their loss,” a State Department spokesperson told ABC News on Monday. “We are closely monitoring local authorities’ investigation into the cause of death. We stand ready to provide all appropriate consular assistance.” The couple’s sister-in-law, Tracey Calanog, the wife of Michelle Paul’s brother, said the pair were able to get to an area hospital before dying. “They knew something was going on in their body,” she said. Preliminary reports suggest that Michelle Paul died first. Hospital personnel told loved ones that they were preparing to transport David Paul, an Air Force veteran, to Australia for further treatment. The U.S. Embassy in Fiji reportedly declined to comment on the couple’s death, but it did say the Fiji government had been warning people of a dangerous flu virus in the region.