A third American has mysteriously died at a resort in the Dominican Republic. A Pennsylvania woman was reported dead last month just five days before a Maryland couple apparently died under similar circumstances.

The Pennsylvania woman's family says she died from the same lung condition as the Maryland couple, but it's unclear how they died, reports CBS News' David Begnaud. The State Department and FBI are looking into the deaths.

In a statement on Wednesday, the Grand Bahia Príncipe said, "Mrs. Schaup-Werner's cause of death was determined to be a heart attack, aligning with official statements provided by Mr. Werner, who confirmed she had a history of heart conditions."

Miranda Schaup-Werner, 41, was found dead at the Grand Bahia Príncipe Bouganville on May 25 where she was celebrating her ninth anniversary with her husband. The family says Schaup-Werner collapsed and died, shortly after having a drink at the hotel.

The U.S. State Department confirms Schaup-Werner died five days before Edward Holmes and Cynthia Day were found dead in their hotel room at the Grand Bahia Príncipe La Romana. An autopsy found the couple had respiratory failure and pulmonary edema, a condition caused by excess fluid in the lungs.

Hotel staff members say they found the couple in their room and unresponsive. There were no signs of violence and relatives of all three Americans say they were healthy.

