The family of Joseph Allen, 55, told NBC News that he was found unresponsive in his hotel room at the Terra Linda Resort on June 13 while on a trip to celebrate a friend's birthday.
"The maid opens the door, screams, slams the door — my brother is on the floor, dead,'' Jason Allen said.
Jason Allen said that his brother skipped dinner that night, telling friends that he wasn't feeling well.
The family said Joseph Allen had stayed at the Terra Linda Resort many times before. The resort did not respond to a request for comment from NBC News.
The news of Joseph Allen's death also comes after a group of diehard Jimmy Buffett fans said they became violently ill during a trip to the Dominican Republic in April.
None of the deaths have been connected by Dominican Republic officials or the U.S. State Department, which has declined to comment on reports that tainted alcohol could have played a role in the string of American deaths.
Less than two years ago, the Dominican National Police shut down five labs manufacturing alcohol and seized 100 tanks of product that were unsuitable for human consumption.
Joseph Allen's family has now become part of a group searching for answers about the loss of their loved ones. His family is trying to bring his body back to the U.S. in an attempt to determine what happened.
"I do feel like there is something that is off, with him ... dying so suddenly,'' Jason Allen said.
The State Department said authorities in the Dominican Republic have asked the FBI for help with toxicology reports, which could take up to 30 days.
"The safety and security of U.S. citizens that live in, work in, and visit the Dominican Republic remains our highest priority,'' U.S. ambassador Robin Bernstein said in a statement. "These incidents are tragic and we offer our deepest condolences to those personally impacted."
Javier Garcia, the minister of tourism in the Dominican Republic, said in a press conference earlier this week that the deaths were "completely isolated" incidents.