Three American tourists were found dead at a Bahamas resort following a “health emergency,” and another U.S. citizen was airlifted to a hospital for treatment.

On Saturday, Dr. Michael Darville – the Bahamas Minister of Health and Wellness – told Eyewitness News Bahamas that guests at the Sandals Emerald Bay in Exuma were taken to a health clinic on Thursday. The ill patients were treated for nausea and vomiting, then they were released.

Shortly after 9 a.m. on Friday, staff at the Sandals Emerald Bay reportedly contacted the George Town Police Station regarding a man that was found unresponsive in a villa. While authorities were en route, another man and woman were also found unresponsive in another villa, according to police.

BuzzFeed News reported, “On arriving at the scene, police found a ‘caucasian male lying on the ground unresponsive’ in the bedroom of the first villa. A doctor later pronounced the victim dead.”

In another villa, authorities discovered an unresponsive “caucasian male slumped against a wall in a bathroom” and an unresponsive “caucasian female” on the bed, according to the Royal Bahamas Police Force.

“Both individuals showed signs of convulsion,” police said.

None of the victims had any signs of trauma, according to authorities. Acting Prime Minister Chester Cooper said that the cause of death is unknown as of Friday. Police are investigating the deaths, but no foul play is suspected.