(NEXSTAR) — Authorities in Costa Rica now believe carbon monoxide poisoning may be to blame for the March death of Miller Gardner, the 14-year-old son of former New York Yankees outfielder Brett Gardner. Costa Rican Judicial Investigative Agency (OIJ) General Director Randall Zúñiga said duri ng a Monday press conference that high levels of carbon monoxide contamination were detected in the hotel room where Gardner and his family had been staying, according to NBC News and ABC News. The room, officials said, was next to "a machine room" that is now believed to be the source of contamination. According to Zúñiga, investigators found carbon monoxide levels of up to 600 parts per million — carbon monoxide becomes dangerous at just 101 parts per million, alarm maker Kidde warns. Miller died “peacefully” in his sleep, his family said last month. His death was not believed to be suspicious, and investigators initially suspected that it was caused by asphyxiation after “food intoxication.” However, asphyxiation was later ruled out. Costa Rican National Police said the teen's respiratory tract was clear and noted that additional tests were being done. Zúñiga noted Monday that while high levels of the hazardous gas were found in the hotel room, a complete toxicology report on Miller is still to come, ESPN reports. Brett Gardner of the New York Yankees poses with his family prior to an event at the MLB Fan Cave in August 2013 in New York City. (Paige Calamari/MLB via Getty Images) An official told ESPN on Tuesday that Miller's family members — many of whom also fell ill, his parents said in an earlier statement — blamed food from a restaurant for their sickness. Costa Rica authorities had previously indicated that food poisoning may still be connected to the teen's death. A doctor who claimed his team helped to treat Miller told People last week that the teen and his family had "gastrointestinal symptoms." What are the ‘torpedo bats’ some MLB players are using, and are they legal? In a statement shared with ABC, the Arenas Del Mar Beachfront & Rainforest Resort, where the Gardner family had been staying, said it was "heartbroken by the tragic loss." "We trust that the forensic process will objectively, clearly, and conclusively clarify the causes of this unfortunate incident," the statement added. The resort noted to People that the family did not eat at any of its restaurants "for lunch or dinner" the day before Miller's death. Brett Gardner and his wife, Jessica, confirmed their son's death in a statement shared via the Yankees on March 23. The couple, who share another son, Hunter, said they had "so many questions and so few answers." “Miller was a beloved son and brother and we cannot yet comprehend our life without his infectious smile,” the statement continued. “He loved football, baseball, golf, hunting, fishing, his family and his friends. He lived life to the fullest every single day.” In a separate statement, the team wrote that “the Yankees family is filled with grief after learning of the passing of Miller Gardner.” The team honored Miller ahead of their Opening Day game against the Milwaukee Brewers last week. The New York Yankees line up for the National Anthem as a tribute to former New York Yankee Brett Gardner's son, Miller, is seen on Opening Day at Yankee Stadium on March 27, 2025, in New York City. (Photo by Mike Stobe/Getty Images) Brett Gardner, a native of South Carolina who attended the College of Charleston, was drafted by the Yankees in 2008. He spent all of his major league career with New York, playing in the 2009 World Series that the team would secure and earning a Gold Glove in 2016. Miller Gardner had been playing football in South Carolina, ESPN reports, and wore No. 11, the same number worn by his father while he played for the Yankees. Miller also played as an outfielder and pitcher on the baseball diamond, according to The Athletic. Gardner last played with the Yankees in 2021. Nexstar's Michael Bartiromo contributed to this report. ...read more read less