Timeline: Mysterious deaths of U.S. tourists reported in Dominican Republic

A rash of U.S. tourist deaths in the Dominican Republic have been reported across the Caribbean island nation.

The deaths, which have been brought to light by family and friends, mostly involve people who were believed to be generally healthy and showed no signs of illness before their trips.

U.S. officials have not said the deaths are connected, and the State Department said there has not been an uptick in American citizen deaths reported to the department.

Tourism officials in the Dominican Republic said that the FBI and health specialists were investigating many of the cases.

Here are 13 Americans reported to have died between 2016 and 2019:

On Sept. 17, 2016, Barbara Diane Maser-Mitchell, 69, of Pennsylvania, died during her stay at the Excellence resort in Punta Cana, where she went to celebrate her birthday with her son and his longtime companion, Fox News said. On her second day at the resort, Maser-Mitchell said she felt ill after having cocktails and went to her room. Her family later contacted a resort doctor. In the ambulance on the way to the hospital, she went into cardiac arrest. Authorities said the official cause of death was a heart attack, Fox News reported.

On April 18, 2018, Chris Palmer, 41, of Kansas, died while staying at the Villa Cocotal Palma resort in Punta Cana, according to Fox News. During his stay, Palmer told friends he was feeling ill and had a bad headache, Fox News reported. At some point on April 18, Palmer was found dead in his room after aspirating his own vomit, Dominican authorities said. Palmer had pulmonary edema and that the official cause of death was a heart attack, the network reported.

In June 2018, Yvette Monique Sport, 51, of Pennsylvania, died after arriving at Bahia Principe resort in Punta Cana, family said. Her sister, Felecia Nieves, said Sport had a drink from the minibar inside her hotel room, went to bed and never woke up. "Heart attack" was listed as the cause of death.

In July 2018, 45-year-old David Harrison, of Maryland, felt sick one night while vacationing at a different resort in the Dominican Republic, according to his wife, Dawn McCoy. She said she called repeatedly for an ambulance but was told by staff that the resort doctor must check him first, according to Fox News. McCoy said it took a long time for a doctor to arrive and he died. Harrison was said to be in good health, and the official cause of death was pulmonary edema and heart attack.

On January 26, 2019, Jerry Curran, 78, a retired Ohio police officer who had recently moved to Florida, died after falling ill during a vacation at a Dreams Resort in Punta Cana, family told WKYC-TV. After having dinner and drinks on the night of their arrival, Curran became ill and spent the next couple of days in bed. He was later put on a ventilator at the hospital before being taken into surgery and died about eight hours later, his daughter told the station. The cause of death was listed as cerebral hypoxia, pulmonary edema, subdural hematoma, and severe encephalitic cranial trauma.

In April 2019, Robert Bell Wallace, 67, became sick soon after drinking a scotch from the room minibar at the Hard Rock Hotel & Casino resort in Punta Cana, family told Fox News. He was in the Dominican Republic to attend his stepson's wedding. His niece, Chloe Arnold, said a hotel doctor checked Wallace, then decided that he needed to be hospitalized. He died on April 14 with the cause listed as a heart attack.

On May 25, 2019, Miranda Schaup-Werner, 41, of Pennsylvania, was preparing to dine with her husband when she began to feel ill and subsequently died at the Luxury Bahia Principe Bouganville hotel in La Romana, operated by Bahia Principe Hotels & Resorts. A family spokesman told news outlets that she collapsed after getting a drink from the minibar. Her death certificate mentioned pulmonary edema and cardiac abnormalities, according to Fox News, while the cause of death was ruled a heart attack.

On May 30, 2019, Edward Holmes, 63, and Cynthia Day, 49, both of Maryland, were found dead at Grand Bahia Principe La Romana, a resort also operated by Bahia Principe Hotels & Resorts. The couple was found unresponsive in their room by a resort employee who went in after they failed to check out. A preliminary autopsy listed pulmonary edema and internal bleeding, according to Fox News. Holmes was listed as having an enlarged heart and cirrhosis of the liver.

On June 11, 2019, Leyla Cox, 53, of New York, was found dead of a heart attack in her hotel room in the Dominican Republic. Cox, from New Brighton, went on vacation alone and was expected to return a week later. Her son, 25-year-old Will Cox, told Fox News that Dominican authorities were pressuring him to have his mother's body embalmed or cremated before its return to the U.S.

On June 13, 2019, Joseph Allen, 55, of New Jersey, was on vacation at the Terra Linda resort in Sosua to celebrate a friend's birthday when he was found dead in his hotel room after feeling ill the night before, his brother told Essence Magazine. In a letter to New Jersey senator Bob Menendez, his brother said that Allen "just had a physical before his trip that showed him to be in very good shape with no issues."

On June 17, 2019, Vittorio Caruso, 56, of New York, died after becoming critically ill at the Boca Chica Resort in Santo Domingo, Fox News reported. Family said he traveled alone, and they were told that Caruso was brought by ambulance to the hospital in "respiratory distress after drinking something." Authorities reportedly said Caruso died of respiratory failure, while relatives were awaiting an autopsy report.

On June 25, 2019, Khalid Adkins, of Colorado, reportedly died after falling critically ill while on a vacation with his daughter in the Dominican Republic. When he boarded his return flight to the U.S., he was dripping with sweat and vomited in the plane's bathroom before being asked to disembark, his sister-in-law told news outlets. He was hospitalized in Santo Domingo, where staff told family that his breathing was "really bad" and that his kidneys were failing. He died days later, FOX 31 reported.

The U.S. State Department said it was "closely monitoring" ongoing investigations by Dominican authorities into several of the recent deaths of U.S. citizens.

"We have no higher priority than the safety and welfare of U.S. citizens abroad," a State Department spokesperson said in a statement. "Millions of Americans travel to the Dominican Republic every year. While the overwhelming majority travel without incident, we want to assure all Americans that we continue to work actively with the Dominican authorities at the very highest levels to ensure that U.S. citizens are safe and feel safe while in the Dominican Republic."

This story was reported from Los Angeles.