The authorities are investigating the fact that the anti-freezer alcohol could have caused the mysterious death of many American tourists in the Dominican Republic.
The FBI joined the investigation after the announcement of at least eight new American tourists who became ill while they were on vacation at the Hard Rock Hotel & Casino and Bahia Principe in the Dominican Republic.
Police are trying to determine if the drinks contain toxic substances such as methanol, which is commonly used in antifreeze, according to the New York Post. The FBI performs blood tests.
Many tourists would have drunk alcohol in their hotel's minibar before getting sick. Other vacationers also reported being violently ill while traveling in the Caribbean crossroads, although they eventually recovered.
The Dominican government and the hotels maintained that the deaths were due to natural causes.
A New York Post reporter who went to the Dominican Republic "noted that the vodka in the room had a strong, strange odor resembling pure alcohol," according to the article.
Lawrence Kobilinsky, professor of forensic science, said the symptoms of methanol intoxication include nausea, vomiting and diarrhea – symptoms that have also been reported by some tourists.