Officials in Costa Rica have confirmed the official cause of death of Miller Gardner, the 14-year-old son of former New York Yankees player Brett Gardner who died under mysterious circumstances on March 21 while on a family vacation. The initial investigation in the days that followed Miller’s tragic passing focused on asphyxiation, which was later ruled out. The investigation then pivoted to food poisoning as a possible cause of death, but on Wednesday night, Costa Rican Judicial Investigative Agency (OIJ) Director Randall Zúñiga said the toxicology results confirmed that he died as a result of carbon monoxide poisoning. "It’s important to note that adjacent to this room is a dedicated machine room, where it’s believed there may be some type of contamination toward these rooms," Zúñiga said. CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COM Zúñiga said Miller was tested for carboxyhemoglobin, a compound generated when carbon monoxide binds to hemoglobin in the blood. The test showed a saturation level of 64%. It is considered lethal when carboxyhemoglobin saturation exceeds 50%. The Gardner family stayed at the Arenas Del Mar hotel in Manuel Antonio. Earlier this week, the OIJ suggested that carbon monoxide poisoning was likely the cause of death, but officials at the hotel denied those claims. A hotel spokesperson told Fox News Digital that the levels in the hotel room "were non-existent and non-lethal." DEATH PROBE OF EX-YANKEE'S SON TRIGGERS CARBON MONOXIDE WARNINGS FROM EXPERTS Fox News Digital reached out to the spokesperson again following Wednesday’s announcement. The Gardner family said in a statement following Miller’s passing that several family members fell ill during the trip. "We have so many questions and so few answers at this point, but we do know that he passed away peacefully in his sleep on the morning of Friday, March 21st," the statement read. "Miller was a beloved son and brother and we cannot yet comprehend our life without his infectious smile. He loved football, baseball, golf, hunting, fishing, his family and his friends. He lived life to the fullest every single day." CLICK HERE TO GET THE FOX NEWS APP Gardner was an outfielder for the Yankees for 14 seasons and was on the team when they won their last World Series title in 2009. He spent his entire career in the Bronx, last playing in 2021. Fox News' Ashley J. DiMella, Ryan Morik, and The Associated Press contributed to this report. Follow Fox News Digital’s sports coverage on X, and subscribe to the Fox News Sports Huddle newsletter.