A young couple from Texas has reportedly passed away during a vacation in Fiji, according to members of their families.

Authorities notified David and Michelle Paul’s loved ones of the couple’s sudden death. Health officials are currently trying to find a cause of death and believe a disease was at the root.

Tracey Calanog, the sister-in-law to the couple said family members received the devastating call the day before the couple planned on returning home. A State Department official is confirming they are monitoring the ongoing local investigation.

"We offer our sincerest condolences to the family on their loss. We are closely monitoring local authorities' investigation into the cause of death," a department spokesperson said. "We stand ready to provide all appropriate consular assistance."

Calanog told WFAA that the couple may have contracted an unknown virus strong enough to kill two healthy young people. The flu has reportedly been ruled out as a possible cause of death. "They knew something was going on in their body and were able to get to the hospital," Calanog said on Monday (June 3).

The family says Michelle Paul died first and hospital workers told the family that they were planning to transport David Paul to Australia for further treatment, but he passed away before that was possible. "They were planning an amazing vacation," Calanog said.

The couple's remains reportedly cannot be returned to the United States until a cause of death is determined.