Relatives and the former supervisor of a New York woman who died suddenly on June 10 at a luxury resort in Punta Cana are disputing the Dominican Republic Minister of Public Health’s claim that she had several past heart attacks.

On Monday, Public Health Minister Rafael Sanchez Cardenas said at a press conference that Leyla Cox, a New York hospital MRI technician who died suddenly on June 10 in her room at the Excellence resort, had an enlarged heart, high blood pressure and that she had suffered “several past heart attacks.”

But on Wednesday, her supervisor where she worked at the Richmond University Medical Center in Staten Island said that in the roughly 10 years she knew Cox, who was 53, she had not had a heart attack or had any serious medical conditions.

“She seemed to be in good health, she had medical tests here and all were good,” said Kathy Giovinazzo, the assistant vice president of clinical services at the hospital, in an interview with Fox News. “In all the years I knew her, I never knew her to have a heart attack.”

Dominican authorities have told the family that Cox died of a heart attack, but the family has expressed skepticism, saying that she had been healthy and had shown no signs of illness leading up to her trip to the island to celebrate her 53rd birthday. Prompted by doubts, her son, William Cox, successfully fought to get Dominican authorities to send a vial of her blood to the U.S. for toxicological testing.

Cox’s son accuses Dominican authorities of lying to avoid accountability.

“In the 25 years I’ve been alive, my mother did not have a heart attack,” he said, adding that others in the family said the Sanchez Cardenas characterization of Leyla Cox’s health were untrue.

"They're lying," Cox said. "It's been like this from the beginning since she died. They give misinformation. They're trying to cover up."

The spokesman for the Ministry of Public Health told Fox News on Wednesday that Sanchez Cardenas was "stating facts that came directly from forensic and pathological tests."

"Those tests tell you a person's cause of death and any past medical conditions," said Carlos Suero, the spokesman. "People come to the Dominican Republic with medical conditions and if they die here, they want to blame it on the Dominican Republic."

Leyla Cox's death was one of a rash of deaths of U.S. tourists in the Dominican Republic since last year that have been made public by their loved ones. The relatives of most of the nine U.S. tourists -- whose deaths occurred under seemingly similar circumstances --have raised doubts about the accounts they've been given by Dominican authorities.

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Several are planning to conduct their own tests in the United States. Since Dominican authorities have declared nearly all the deaths to have occurred because of natural causes, they have declined to conduct toxicological tests, leading to complaints from the relatives.

"Once a death is declared to be from natural causes, they have a different process," Cox said. "They can just declare any death to be of natural causes because then they're not held accountable."

On Tuesday afternoon, the Dominican attorney general approved Will Cox's request that a blood sample from his mother be sent to the U.S. for toxicological tests. The hospital where she worked agreed to conduct the tests at no charge to her family.

Cox had wanted toxicological tests to be done in the Dominican Republic but was told that the machines were not working. He is trying to get her ashes sent to the U.S.

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Cox said it has been nothing short of an ordeal to extract information from the resort and Dominican authorities about the details of his mother's death. He said that while a U.S. embassy staff member was in touch with him every day, and was helpful in some instances, in others he gave incomplete or erroneous information.

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Speaking on "America's Newsroom" Wednesday, Cox credited an official at the U.S. Embassy for helping him obtain blood and urine samples for a separate toxicology report in the United States. He said he initially received an incomplete police report, while the resort's first statement on his mother's death was incorrect.

"I felt like I was pushed up against the wall and didn't have any options and they almost forced me to cremate the body within 24 hours," said Cox, expressing fear that he'll never get a clear answer on how his mother died.