Miller Gardner‘s cause of death has been confirmed by Costa Rica authorities.
The 14-year-old son of former New York Yankees star Brett Gardner died of exposure to poisonous gases including carbon monoxide poisoning, Us Weekly confirmed on Wednesday, April 2.
Miller’s cause of death was revealed by Randall Zúñiga, General Director of Costa Rica’s Judicial Investigative Agency (OIJ), who shared the toxicology results in a statement to press.
“In the carboxyhemoglobin test, a saturation level of 64 percent was found,” Zúñiga said. “In such cases, when concentrations exceed 50 percent carboxyhemoglobin, it is considered lethal. In this particular case, with a saturation of 64 percent, the level is clearly well above that lethal threshold.”
Celebrity Deaths of 2025: Stars We’ve Lost
He continued, “Therefore, this confirms the police hypothesis that the death was caused by exposure to poisonous gases, specifically carbon monoxide. With this, the case is practically closed. The only step remaining is for the toxicology report from the OIJ Forensic Sciences Department to be forwarded to the Legal Medicine Department, so the expert can include it in the autopsy report.”
He noted that additional “tests were also conducted, such as drug screenings — including for fentanyl — and all came back negative in relation to the symptoms shown by young Gardner.”
“In this particular case, a strictly scientific investigation was carried out, which allowed the real truth of the facts to be determined. In fact, during the autopsy, the organs of young Gardner showed a very specific layer that forms when a person dies from carbon monoxide poisoning or gas inhalation. That emphysema was both visible and very noticeable during the autopsy,” Zúñiga said.
Miller died on March 21 while he was vacationing with his family in Costa Rica. They were staying at the Arenas Del Mar Beachfront and Rainforest Resort when Miller’s body was found unresponsive.
Authorities Say Carbon Monoxide Found in Gardner Family Hotel Room
A preliminary cause of death was ruled to be asphyxia “after a possible intoxication after apparently ingesting some food,” the OIJ reported on March 24.
However, Zúñiga said in a Monday, March 31, virtual communication to the press that Miller “may have died from inhaling” carbon monoxide.
The OIJ official confirmed “high levels of carbon monoxide contamination” were detected in the family’s hotel room as part of testing carried out by a “specialized hazardous atmosphere team” from the Fire Department and forensic engineering performed by OIJ investigators.
“It’s also important to note that next to [the family’s] room there is a specialized machine room, from which it is believed some form of contamination may have reached the guest rooms, potentially causing the incident,” he suggested at the time.
Yankees’ Aaron Judge Calls Brett Gardner a ‘Second Dad’ After Son’s Death
Zúñiga had said that the OIJ notified both the local Fire Department and the Ministry of Health in order for them to “take appropriate action regarding this confirmed contamination in the room.” He noted that the OIJ was working in tandem with the FBI in the U.S. as they awaited the toxicology results.
“Nonetheless, the initial investigative findings indicate that the incident was due to this contamination, with levels as high as 600 parts per million detected — when the appropriate level in this case should be zero,” Zúñiga said Monday.
A spokesperson for the Arenas Del Mar Beachfront and Rainforest Resort responded to the OIJ’s carbon monoxide reports in a Monday statement to Us Weekly, saying, “We deeply regret the recent death of a minor at our facilities due to unconfirmed causes. We express our sincere condolences to the child’s family and loved ones in this time of immense grief.”
The statement added: “We trust that the forensic process will objectively, clearly, and conclusively clarify the real causes of this unfortunate incident. For the time being, the investigation will continue with the analysis of the various theories put forward by the judicial authorities.”
Miller Gardner’s Death Has Been ‘Almost Too Much’ for His Baseball Team
Last month, Miller’s parents — Brett, 41, and his wife, Jessica Gardner — made the tragic announcement that they had lost their son.
“With heavy hearts, we are saddened to announce the passing of our youngest son, Miller. He was 14 years old and has left us far too soon after falling ill along with several other family members while on vacation,” they pair said in a joint statement. “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.”
They continued: “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.”
On Sunday, March 30, a spokesperson for the Judicial Investigation Agency’s Press Office told Us that Miller’s body had been discharged but “out of respect for the family it has not been disclosed who it was released to.”
Miller Gardner’s Body Released Before Autopsy Result: Authorities
Us later confirmed that a body cannot be released from a morgue in Costa Rica unless a family member or a legal representative submits an official request. Miller’s autopsy is expected to be completed within two months.
As they cope with loss and grief, the Garders are honoring Miller’s legacy. An obituary published in Charleston, South Carolina’s Post and Courier on behalf of the family asked that donations be made in his honor to the Make-a-Wish Foundation, a non-profit that fulfills the wishes of young people battling life-threatening medical conditions.
“The Gardners have seen the organization’s impact firsthand on numerous occasions and have always been deeply moved by the hope, strength, and inspiration each wish provides for children and families facing difficult times,” Miller’s obituary read. “In this time of unimaginable loss, the family prays that joy and healing will come to others who share their grief.”
