on Tuesday, Shark Tank star Barbara said her brother’s friend discovered his lifeless body on the floor of their suite.
But a post-mortem examination has never revealed his cause of death.
It is unclear which hotel John was staying in at the time.
SEVEN MYSTERY DEATHS A recent spate of mysterious and sudden deaths of American tourists at resorts in the Dominican Republic has raised concerns that the deaths may not be coincidental.
Seven tourists died after drinking from the minibar at two luxury resorts on the Caribbean island.
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.
American David Harrison, 45, of Maryland, died in July last year at the same Hard Rock Hotel resort after a sudden heart attack.
His heartbroken widow Dawn McCoy said her husband was mumbling inanely and complained of a "very potent, strange smell".
We have so many questions ... We don’t want this to happen to anyone else
Chloe Arnold, Niece of Robert Bell Wallace Miranda Schaup-Werner, 41, collapsed died in her room after having a drink from her minibar at the Luxury Bahia Principe Bouganville in La Romana, 70 miles west of Punta Cana
Five days later, Edward Holmes, 63, and Cynthia Day, 49, were found dead in their room at the neighbouring Grand Bahia Principe resort.
And it has since emerged Yvette Monique Short, 51, passed away she had a drink from the minibar.
It wasn’t clear if Mr Holmes and Ms Day drank from the minibar, and their deaths were attributed by officials to respiratory failure.
Dominican officials said Mr Schaup-Werner suffered a heart attack, but her brother-in-law, Jay McDonald, insisted she died of respiratory failure and had drunk from the bar.
Another woman who stayed at the Bahia Principe this week claimed that she “vomited blood” after drinking a 7-UP from her minibar.
Awilda Montes , from New York, US, believes the 7-Up she drank at the Luxury Bahia Principe Bouganville resort, in the Dominican Republic, contained bleach.
Awilda initially thought it was an accident, but she now thinks she may have been spiked, following the deaths of three people at the resort last month.
We started to see unusual activity in April when six people reported being ill on the island, but in June it exploded.
Patrick Quade She told CBS News: "I was cautious when I took a gulp of it. I immediately felt it burn me, burn my mouth, burn my tongue. My mouth was on fire.
Dominican authorities said post-mortem examinations revealed all six died of natural causes.
The families of at least three people who died on the island last month were told that their loved ones died from pulmonary edema and respiratory failure.
Other victims were said to have died of heart attacks.
A total of 30 million tourists have visited the island in the past five years, including 2.7 million Americans every year.
Former FBI deputy assistant director Danny Coulson told FOX News on Tuesday: "It doesn't make much sense.
"This thing doesn't pass the smell test. These people didn't have simultaneous heart attacks.
VOMITING BLOOD "There needs to be a major investigation."
Authorities from both the US and the Dominican Republic are currently on the ground investigating the deaths amid fears the tourists may have been poisoned.
“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.
The US State Department told Fox News: “We can confirm the death of a US citizen in April 2019 in the Dominican Republic.
“We offer our sincerest condolences to the family for their loss.
“Out of respect for the family during this difficult time, we do not have additional information to provide.”
Robert Bell Wallace, 67, right, of California, fell ill and died after drinking a whisky at the Hard Rock Hotel in the Dominican Republic Credit: Fox News Miranda Schaup-Werner, 41, died in May after a drink from a minibar at the Bahia Principe La Romana Hotel Credit: Twitter David Harrison, left, died in July last year at the same Hard Rock Hotel resort under similar, sudden circumstances The resort apologised and offered her and her boyfriend a meal and a massage, according to reports.
In a statement on the Grupo Pinero website the company that owns the hotel said: “In regards to the two unfortunate events that took place in the Dominican Republic, and after inaccurate and false information has been spread, Bahia Principe Hotels & Resorts would like to express our deep respect to the authorities and the ongoing investigations.
“We reiterate our firm commitment to collaborating completely with the authorities and hope for a prompt resolution of their inquiries and actions and will not be making any further statements that may interfere with them.
“The safety and comfort of our guests and staff stand at the core of our company values, and we work daily to ensure it.
“We reiterate that we completely disagree with the dissemination of false information issued publicly which threatens the image and reputation of the company and the integrity and rights of our employees and their families, reserving, where necessary, the right to take the appropriate legal action.”
The Sun Online has contacted The Hard Rock Hotel and the Dominican Republic Tourist Board for comment.
Yvette Monique Sport, 51, died in June of 2018 on a holiday with her fiancé Credit: Fox 29 David Harrison's, left, death was ruled a heart attack by authorities in the Dominican Republic Credit: Dawn McCoy Robert Wallace, right, was allegedly in good health and an avid skier Credit: Fox News Engaged Maryland couple Edward Holmes, 63, left, and Cynthia Day, 49, right, died in their room at the Bahia Principe La Romana on May 30 Credit: Facebook Awilda Montes, from New York, believes her drink was spiked with bleach at the same hotel where three others have died Credit: cbs news
Brooklyn woman claims she vomited blood after drinking a beverage from her hotel room's mini bar in the Dominican Republic We pay for your stories! Do you have a story for The Sun Online news team? Email us at tips@the-sun.co.uk or call 0207 782 4368. You can WhatsApp us on 07810 791 502. We pay for videos too. Click here to upload yours