Carbon monoxide poisoning killed three U.S. touristsin the Bahamas in May, police announced Tuesday.
Authorities did not provide further details, saying the deaths were still under investigation.
The victims had been identified as Michael Phillips, 68, and Robbie Phillips, 65, from Tennessee; and Vincent Chiarella, 64, from Florida.
Chiarella's wife, Donnis Chiarella, 65, was found alive and airlifted to New Providence for medical treatment, then transferred to a hospital in Florida.
The couples were staying next to each other in separate villas in the same building at the Sandals Emerald Bay resort on the island of Exuma. It was not clear if the villas had carbon monoxide detectors, and if they did, whether they were working.
Police have said that all four tourists went to a doctor the night before their bodies were discovered and had complained of feeling ill.
It was not clear what was the source of carbon monoxide that killed them. A Sandals spokeswoman referred all questions to police, while Bahamian police spokesman Audley Peters said he was not able to provide the information "at this time" and did not respond to further questions.
Sampleshad been sent to a lab in Philadelphia for toxicology reports.
Last month, in response to the three deaths, Sandals said it had installed carbon monoxide detectors in all Emerald Bay guest rooms, with plans to install detectors in every guest room in all its resorts.
In a statement to CBS News Tuesday evening which echoed a similar one it released about a month ago, Sandals said that authorities determined the deaths were caused by an "isolated incident in one standalone structure that housed two individual guest rooms."
In its previous statement, Sandals said the deaths were "in no way linked to the resort's air conditioning system, food and beverage service, landscaping services or foul play."
The deaths come seven years after a Delaware family became seriously ill at a resort in the U.S. Virgin Islands. U.S. authorities determined that methyl bromide, a highly toxic pesticide banned for indoor residential use in 1984, was to blame and had been used at that resort several times.
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