The FBI is investigating the deaths of three Americans staying at resorts in the Dominican Republic in recent weeks, NPR reported Wednesday.
Since news of the deaths broke, relatives of four other Americans who died there over the past year have spoken up, including real estate mogul and "Shark Tank" judge Barbara Corcoran.
Similarities among the deaths have been reported: They happened suddenly, several after having an alcoholic drink. But authorities have not established a connection.
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Robin Bernstein, U.S. ambassador to the Dominican Republic, said the FBI is conducting toxicology tests, which could take up to a month to complete.
"The safety and security of U.S. citizens that live in, work in, and visit the Dominican Republic remains our highest priority," said Bernstein in a statement. "These incidents are tragic and we offer our deepest condolences to those personally impacted."
Meanwhile, the families of Maryland couple Nathaniel Holmes, 63, and Cynthia Ann Day, 49, have flown their bodies back to the U.S. and are preparing to have autopsies and toxicology tests performed. The couple, who were engaged, were found dead in their room at the Grand Bahia Principe La Romana resort on May 30. An autopsy in the Dominican Republic found that both died of respiratory failure and pulmonary edema, a condition in which the lungs fill with fluid.
Five days earlier, Miranda Schaup-Werner, 41, died of the same cause after checking in to a resort owned by the same company. She experienced respiratory failure not long after consuming a drink from the minibar in her hotel room, authorities in the Dominican Republic said.
On Wednesday, Corcoran said her brother John, 65, was found dead in his hotel room of a heart attack while vacationing in the Dominican Republic in April.
On Jun. 6, family members of Pennsylvanian Yvette Monique Sport, 51, told NBC10 she died last June at a Bahia Principe hotel after she drank a beverage from the hotel's minibar.
But Bernstein, the U.S. ambassador, said a link between the older and newer cases is not yet evident. "At this time, we have no indication of any connection between those tragic losses and the cases currently under investigation," she said.
Six million people visit the Dominican Republic each year, half of those from the United States.