Police found a man "slumped against a bathroom wall" after a screaming woman's limbs became "swollen" as mystery surrounds three deaths at a luxury resort in the Bahamas.
The trio of Americans died on Friday while staying at Sandals Emerald Bay.
A fourth person was taken to Princess Margaret Hospital by helicopter, Acting Prime Minister Chester Cooper said.
There was no evidence of any trauma on any of the victims, according to The Royal Bahamas Police Force, and foul play is not suspected.
The three victims, two men and one woman, were found in two separate villas.
"The officers found a Caucasian male slumped against a wall in a bathroom, unresponsive," investigators told CNN.
Sandals Emerald Bay resort in the Bahamas
They added: "The woman was also unresponsive. Both individuals showed signs of convulsion. The officers examined the bodies and found no signs of trauma."
One of the people who died has been identified as Vincent Chiarella of Birmingham, Alabama according to his son Austin Chiarella.
Mr Chiarella's wife Donnis was also injured while the couple were celebrating their anniversary, he told ABC News.
Austin told the station his mother had woken up and couldn't move while Mr Chiarella “was laying on the floor.”
“Her legs and arms was swollen and she couldn’t move and she screamed to get someone to come in the door,” he said.
The night before the Chiarellas were found, they had complained about feeling unwell and been treated at a local medical facility before returning to their villa.
The investigation into the tragedy remains ongoing and no cause of death has yet been given until autopsy results have been completed.
The luxurious rooms in the Bahamas resort
However a guest at the resort has offered a theory about what may have caused the three deaths.
"Three of our neighbours in the building right next to us died and a fourth was airlifted in critical condition early yesterday," Chris Coucheron-Aamot posted on Facebook on Saturday.
"There was crime scene tape and security guards all around our unit.
"It sounds like it may have been a fault with the a/c in the unit, causing a toxic coolant leak."
Chester Cooper said: "I am advised that foul play is not suspected"
"I have asked Minister of Health and Wellness Dr. Michael Darville to lead a delegation this evening to Exuma of Health and Wellness, Environment and Public Works officials.
“We offer our thoughts and prayers to the families affected.”
Chris Coucheron-Aamot, a guest at the resort, shared a possible theory on Facebook
A statement from Sandals resort was released confirming the deaths.
It read: “We are actively working to support both the investigation and the guests’ families in every way possible during this difficult time.
"Out of respect for the privacy of our guests, we cannot disclose further information at this time."
Sandals Emerald Bay is among a dozen all-inclusive locations in the Atlantic and Caribbean.
The resort charges thousands for a multi-night stay, while some suites offer butler services, beach access and private patios for guests.
The Sandals resort has three swimming pools, 11 restaurants and a golf course among its facilities