Six people have died in recent months in the Hard Rock Hotel & Casino, Bahia Principe resort, and a Bahia Principe sister resort, and FBI starts looking into a spate of this mysterious tourist deaths at luxury resorts.

In April, American tourist Robert Bell Wallace, 67, became sick and urinated blood after he had one whisky from his room minibar at the Hard Rock Hotel & Casino in Punta Cana. He was visiting the country for his step-son's wedding.

On May 25, Miranda Schaup-Werner, 41, from Pennsylvania, died after she had a drink from her minibar at the Bahia Principe La Romana.

Five days later, an engaged couple from Maryland, Edward Holmes, 63, and Cynthia Day, 49, died in their room at the same hotel. A hotel employee found them unresponsive in their room after they failed to check out.

In recent days, a Maryland widow went public with concerns about the death of her husband, David Harrison, last year at the same Hard Rock Hotel resort under similar, sudden circumstances.

She told US TV station WTOP: "I started seeing all these other people that were dying of the same exact causes, which made me start to second guess. I no longer feel like my husband died of natural causes.

"We went down there as a happy family, and we came home a broken family. I came home a widow and my 12-year-old son came home fatherless."

A sixth victim, Yvette Monique Sport, 51, of Glenside, died in June of 2018, at a Bahia Principe resort in Punta Cana. She was there with her fiancé, Howard Taltoan, and their friends.

Sport's sister Felecia Nieves told FOX 29: "She was 51 years of age, relatively healthy, no reason for her to go on vacation and die so suddenly."

Nieves said she had a drink from the mini bar inside her hotel room, went to bed and never woke up. Her death certificate lists "heart attack” as the cause of death.

“It’s a complete fabrication ... that you could have as many people and they all have the same cookie-cutter outcome. It’s impossible,” Nieves said.

"We were promised within three months that we would receive a toxicology report to this day, which is almost a year now we’ve got nothing."

Sport's fiance Taltoan said: "I think the state department needs to step in and investigate these deaths something is not right."

However, Dominican authorities said post-mortem examinations revealed all six died of natural causes, but still, their families are searching for answers.

New testing and FBI involvement has marked the first indications that US officials and the Dominican Republic are considering the possibility of something other than natural causes.

70 tourists ”violently ill

Meanwhile, nearly 70 tourists have reported becoming violently ill while vacationing on the island since March, according to iwaspoisoned.com - a website that tracks food-borne illness outbreaks.

In June alone, 52 tourists reported symptoms of vomiting, diarrhoea and fever. More than 45 of them identified themselves as guests at the Hard Rock Hotel & Casino Punta Cana.

Website founder Patrick Quade told the NY Post: "We started to see unusual activity in April when six people reported being ill on the island, but in June it exploded.”

Quade consulted Lee-Ann Jaykus, a food microbiologist in the department of food science at North Carolina State University.

Jaykus said exposure to an insecticide chemical known as organophosphate could result in severe vomiting and diarrhea, and in extreme cases it could cause a cardiac crisis.

The families of at least three people who died at resorts on the island last month were told that their loved ones died from pulmonary edema and respiratory failure.

The resorts are reportedly cooperating with officials.

There is reportedly no medical links between the deaths found thus far, CBS News reported.

The network also reports that the publicity from the tourist deaths has had a negative “economic impact” for the Dominican Republic’s resorts.

“We are deeply saddened by the incident at one of our hotels in La Romana, Dominican Republic, and want to express our deepest condolences to their family and friends,” Bahia Principe Hotel said in a statement after a Maryland couple was found dead in their hotel room at the end of May.