Investigators are probing the possibility of poisoning as causing the sudden deaths of a young couple in Fiji this spring.

As CrimeOnline previously reported, David and Michelle Paul of Fort Worth, Texas, died after becoming violently ill shortly after arriving for their long-planned vacation. Both were reportedly vomiting for several hours before they decided to seek medical help.

“We are both going to doctor now,” Michelle reportedly texted her parents, according to ABC News. “We have been throwing up for 8 hours. Dave has diarrhea. My hands are numb. We will text when we can.”

Though Michelle told her parents that she and her husband both received fluids and anti-nausea medication, their conditions deteriorated. Michelle, 35, died on May 25 and David, 37, passed away on May 27. They left behind a toddler son.

The couple’s sister-in-law, Tracey Calanog, told WFAA that the CDC had ruled out infectious disease and influenza as the cause of death.

“So they have turned their focus to toxins or anything that may have been ingested,” Calanog told the news station, which reports that investigators are working to track the couple’s whereabouts before they became ill, in part to determine what they ate. A video that Michelle took at a restaurant in Fiji is reportedly part of the investigation.

The CDC has “turned their focus to toxins or anything that may have been ingested,” Calanog told WFAA.

The grieving family is planning to have a funeral for the couple once the bodies are returned to the U.S., which is expected to happen within the week, according to the report.