The deaths of three American tourists who perished days apart at sister resorts in the Dominican Republic were determined by toxicology tests to have been the result of natural causes, according to the U.S. State Department.
A spokesperson for the State Department confirms to PEOPLE that the findings regarding the May deaths of Miranda Schaup-Werner, 41, and couple Nathaniel Holmes, 63, and Cynthia Day, 49, were consistent with those presented by Dominican authorities.
Schaup-Werner was determined to have died of a heart attack, while several potential causes for Holmes and Day — including methanol poisoning from tainted alcohol — were ruled out by tests, the State Department said.
“Our condolences and sympathy go out to the families during this difficult time,” the spokesperson said in a statement.
There were no signs of physical violence or foul play, the spokesperson said after at least nine Americans died on the island in recent months.
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Schaup-Werner, of Pennsylvania, died on May 25 while celebrating her 9th anniversary with husband Daniel Werner at the the Luxury Bahia Principe Bouganville hotel in La Romana.
McDonald said in June that Schaup-Werner died of respiratory failure, while a statement from the hotel said she had a heart attack, citing the National Institute of Forensic Sciences and the National Police Investigations Unit.
A statement from the hotel that same month, citing the National Institute of Forensic Sciences and the National Police Investigations Unit, also said that Schaup-Werner’s death was caused by a heart attack.
The resort’s statement said the finding aligned “with official statements provided by Mr. Werner, who confirmed she had a history of heart conditions.”
Daniel Werner declined to comment when reached by PEOPLE on Friday.
Meanwhile, Holmes and Day’s bodies were discovered in their hotel room on May 30, according to a statement released by the Grand Bahia Principe La Romana, where they’d been staying since May 25.
The Dominican Republic National Police later announced an autopsy found the couple died of respiratory failure and pulmonary edema. Day also reportedly suffered cerebral edema.
The engaged couple both had internal bleeding, including in their pancreases, CNN reported, citing authorities in the Dominican Republic, while Holmes also reportedly had an enlarged heart and cirrhosis of the liver.
“The Day and Holmes families have not been provided with any information from the FBI or the Dominican Republic Authorities regarding the deaths,” Steven Bullock, the family spokesperson, tells PEOPLE.
He continues, “The only information that has been received by the families is what is being reported in the media. Our investigation is continuing, and we will not have further comment until we receive the results of our investigation.”
After Holmes and Day’s causes of death were announced, McDonald expressed skepticism that all three had died of respiratory failure.
“They died just five days after, and the cause was determined to be the same, this just puts the whole thing through the stratosphere,” he told Fox News. “Something is going on, and we want to know what it is.”
PEOPLE was unable to reach McDonald for comment.