A high level of carbon monoxide was detected in 14-year-old Miller Gardner's hotel room, Costa Rican Police revealed.

A toxicology report after his death found high levels of carboxyhemoglobin, an indicator of carbon monoxide in the blood, according to a statement from Randall Zúñiga, the director of the Costa Rica Judicial Investigation Agency. Miller Gardner’s test showed a saturation of 64 percent, he said, adding that anything over 50 percent was lethal.

Miller Gardner, the teenage son of former New York Yankees outfielder Brett Gardner, died of carbon monoxide poisoning, authorities in Costa Rica said Wednesday night. Miller Gardner, 14, died March 21 while the family was vacationing in Costa Rica and the cause of his sudden death was unknown before local officials conducted testing and found carboxyhemoglobin to be the cause.

The former New York Yankees outfielder's 14-year-old son died last month during a family vacation in Costa Rica.

The 14-year-old son of former New York Yankees outfielder Brett Gardner died from carbon monoxide poisoning while visiting Costa Rica, local authorities have confirmed .

After initially having disregarded it as a potential cause of death, Costa Rican officials said the teen son of former New York Yankees outfielder Brett Gardner may have died during family vacation as a result of carbon monoxide poisoning.

Costa Rican authorities told reporters that carbon monoxide poisoning may caused the mysterious death of former Yankees star Brett Gardner's son, Miller.

The Costa Rican resort refutes claims that carbon monoxide caused Brett Garner's son Miller’s death, contradicting investigators’ findings.

Authorities in Costa Rica investigating the death of former New York Yankees outfielder Brett Gardner’s teenage son have concluded that he died of carbon monoxide poisoning. Miller Gardner, 14, was found dead on March 21 in his hotel room at the Arenas Del Mar resort in Manuel Antonio,