View of Bavaro beach, in Punta Cana, Dominican Republic, on January 16, 2012.
Wallace's condition worsened and he was hospitalized April 13 after being checked by a hotel doctor, Arnold said.
His heartbroken niece, Chloe Arnold, told Fox News: 'He was fine.
Wallace is the fourth American to die while visiting the Dominican Republic since the end of April. Harrison's wife, Dawn McCoy, was among them: she said that she scuttled a trip she planned to take to the Caribbean country on the first anniversary of her husband's death. "Serious insults and threats have been imposed on some of our more than 15,000 employees and their families, who are the backbone of our company and for whom we cannot remain on the sidelines".
"My husband's story needs to be told ... something's not right in the Dominican Republic", she continued.
So far Investigators say there are no medical connections to link the deaths.
Robert Bell Wallace, 67, died at the resort after having a single whiskey from his room's mini bar in April.
Miranda Schaup-Werner and Yvette Monique Sport died at the Bahia Principe resort. As for Schaup-Werner, Dominican officials said she had a heart attack, but her brother-in-law, Jay McDonald, insisted she died of respiratory failure and had drank from the bar. "Things can happen. But right now we don't really know what's causing this and that's the biggest concern".
"We were having a great time ... and we ended up coming home as a broken family", she told Inside Edition.
According to the Dominican authorities, all four died of natural causes but the families are looking for answers. In a June 7 statement, the Bahia Principe said it has a "firm commitment to collaborate completely with the authorities and hope for a prompt resolution".
For 24 years, Bahia Principe Hotels & Resorts has operated in the Dominican Republic, which is one of the most internationally recognized destinations, and receives 7 million tourists from around the world annually. Dominican authorities also ruled his death was due to pulmonary edema and a heart attack.
The reports of the growing death toll were particularly disturbing to Brooklyn's Awilda Montes, 43, who said she began vomiting blood after drinking soda from her minibar at the Grand Bahia Principe last October - but managed to survive.
Steven Bullock, a lawyer for Day's family, said autopsies and tests will be performed on Day and Holmes in the US.