Caruso had long had high blood pressure, heart disease and lung diseases, the office said.
The United States has not issued a warning reaction specific to the death of the Dominican Republic, and an American official said on Friday that there has been no unusual uptick in reported deaths there.
Caruso, from New York, had lived in the Boca Chica community near Santo Domingo for several years, prosecutors said. His partner, Yomaira Ramirez de Jesus, told prosecutors that Caruso started coughing and feeling breathless on June 1
Almost a week later, Ramirez de Jesus Caruso called her, complaining of breathing needs and chest pain. She found that he received medical care at home, prosecutors say.
Caruso was then transferred to a hospital in Santo Domingo where he suffered from cardiorespiratory arrest and died.
Caruso had been struggling with high blood pressure for nine years and had a long history of chronic obstructive pulmonary disease (COPD), said the law firm's office.
New and previous heart attacks were discovered by the autopsy, the office said. Caruso was a smoker and drank alcohol, per autopsy result.
The body showed no signs of internal or external trauma, according to prosecutors.
The FBI has a law in the Dominican Republic that assists in the toxicity test of three of the 10 known American deaths.
CNN's Theresa Waldrop contributed to this report.