Yvette Nicole Sport was a bride-to-be on a romantic trip to the Dominican Republic with her fiancé. In June 2018, the 51-year-old took a drink from the hotel minibar, went to bed, and never woke up.

At the time, the Pennsylvania woman’s death was classified as a heart attack — but with the news thatseveral American touristshave died at the Bahía Príncipe in Punta Cana, Sport’s cause of death is being investigated once more.

PEOPLE confirms that the both theFBI and the CDCare investigating the mysterious deaths, but the agencies are not releasing any further details about their investigation at this time.

Sport’s family is speaking out — and they believe that there has been a cover-up in the investigation.

“There is something dirty at the bottom of all of this,” Sport’s sister, Felecia Nievestold news station WTXF. “She was 51 years of age, relatively healthy, no reason for her to go on vacation and just die so suddenly.”

Yvette Monique Sport

The U.S. State Department has confirmed that there are at leastsix American touristswho have recently died while on vacation in Punta Cana.

David Harrison, 45, became sick and later died after drinking a soda from the minibar at the Hard Rock Hotel & Casino resort last July while celebrating his anniversary. His wife, Dawn McCoy, tells theWashington Postthat Harrison’s death was classified as a heart attack. “I thought his death was just a fluke,” she told the paper.

Robert Bell Wallace, 67, died in April, also while staying at the Hard Rock. His niece, Chloe Arnold,told Fox Newsthat he became ill after having a drink from the his hotel room. “He was fine,” Arnold said. “On April 11 he had scotch from the minibar. He started feeling very sick, he had blood in his urine and stool right afterward.”

He died three days later, and Arnold claims that authorities have not given them a cause of death. “We have so many questions,” she said. “We don’t want this to happen to anyone else.”

Weeks after Wallace’s death,three more American tourists diedat the Bahía Príncipe properties over a five-day period.

On May 25,Miranda Schaup-Werner, an Allentown, Pennsylvania psychotherapist, 41, collapsed shortly after mixing a drink from the minibar in the Luxury Bahia Principe Bouganville, where she was celebrating her 9th wedding anniversary with husband Daniel Werner.

Five days later, Edward Nathaniel Holmes, 63 and Cynthia Day, 49,were found unresponsive in their hotel room at the Grand Bahia Principe La Romana, which is on the same resort as Luxury Bahia Principe Bouganville. There were no signs of violence.

According to the autopsy report, the couple suffered respiratory failure and fluid accumulation in their lungs, with Day also suffering a cerebral edema, though the cause of the fatal episodes was not clear and toxicology results are still pending.

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Miranda Schaup-Werner Danker Holmes and Cyndi Day

Last week,a Colorado couplewho stayed at the Grand Bahia Principe Hotel alleged that they had become violently ill after being exposed to what they suspect were insecticides through the air conditioning system.

FBI Will Conduct Tests at Resort Where 3 Americans Died

TheFBI confirmed to Foxthat it was joining the investigation into mysterious deaths and illnesses on the island. They will send experts to conduct tests at the Bahia Principe hotels where Schaup-Werner, Holmes and Day died.

Miranda Schaup-Werner and Daniel Werner.

Miranda Schaup-Werner2

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Univision reported that Robin Bernstein, the ambassador of the United States to the Dominican Republic, said last week therecent high-profile incidentsinvolving American tourists in the Caribbean island nation — includingthe assault of a woman at another resort— were isolated cases.

“We have 2.7 million Americans who come to the country and the statistics is that this is a very … unique event,” Bernstein said. “They come to visit the beautiful beaches and enjoy the great culture. Unfortunately sometimes those things happen to people.”

The resorts did not respond on Wednesday to PEOPLE’s request for comment.

source: people.com