An investigation is underway after three American tourists were found dead at a Bahamas resort on Friday, officials said.

The guests were staying at the Sandals Emerald Bay in Exuma, Sandals confirmed.

Resort staff contacted the George Town Police Station shortly after 9 a.m. Friday that a man was found unresponsive in a villa, and while en route it was reported that another man and woman were found unresponsive in another villa, police said.

Police found the man in the first villa lying on the ground with no signs of trauma, authorities said. In the second villa, the man was found “slumped against a wall in a bathroom” and the woman was found on a bed, the Royal Bahamas Police Force said in a statement.

“Both individuals showed signs of convulsion,” police said. No signs of trauma were found on either body.

Bahamas Minister of Health & Wellness Dr. Michael Darville told ABC News that some hotel guests went to a clinic Thursday with nausea and vomiting, were treated and left. Three were later found dead, while a fourth, a woman, was flown to a hospital in New Providence and is in stable condition, he said.

Police said Friday they were working to confirm the identities of the deceased.

The U.S. State Department on Sunday confirmed the deaths of three Americans in the Bahamas.

“We are closely monitoring local authorities’ investigation into the cause of death,” a Department of State spokesperson told ABC News. “We stand ready to provide all appropriate consular assistance. Out of respect for the privacy of the families, we have nothing further to add at this time.”

One of the victims was Vincent Chiarella, of Birmingham, Alabama, his son, Austin Chiarella, confirmed to ABC News.

Vincent Chiarella, who was in his mid-60s, was staying in the Bahamas with his wife, Donnis Chiarella, for their anniversary, their son said.

Donnis Chiarella, who is also in her mid-60s, was the fourth victim who survived, Austin Chiarella said. She is being airlifted to Kendall Regional facility in Florida and should arrive late Saturday afternoon, he said.

Austin Chiarella said he received a call from the U.S. Embassy Friday night with the news and was able to speak with his mother Saturday morning.

“She woke up and my dad was laying there on the floor, and she couldn’t move,” he said. “Her legs and arms was swollen and she couldn’t move and she screamed to get someone to come in the door.”

Donnis Chiarella told her son she had fallen ill on Thursday but “thought she was alright” after she was released from the clinic, he said.

“I am just so heartbroken right now,” Austin Chiarella said. “My dad was everything to me.”

Environmental health scientists, physicians and others are investigating to ensure there was not a public health hazard, said Darville, who called it an “isolated incident.”

“There’s no potential risk to any of the residents on Exuma as well as residents at the resort or any other resort on the on Exuma,” he said.

Acting Prime Minister Chester Cooper said in a statement Friday that the cause of death is unknown but no foul play is suspected.

Sandals said it was “actively working to support both the investigation as well as the guests’ families in every way possible.”

“A health emergency was initially reported and following our protocols we immediately alerted emergency medical professionals and relevant local authorities,” the company said in a statement. “Out of respect for the privacy of our guests, we cannot disclose further information at this time.”

ABC News’ Jason Volack, Caroline Guthrie, Alexandra Faul, Caroline Guthrie, Jasper Ward and Courtney Condron contributed to this report.