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.

Costa Rica authorities confirmed that carbon monoxide poisoning was the cause of death of Miller Gardner, the 14-year-old son of former New York Yankees outfielder Brett Gardner.

The New York Yankees star’s 14-year-old son was found dead in his hotel room during the family’s vacation in Costa Rica.

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.

A blood test for carbon monoxide showed a saturation level of 64% in Gardner’s body, Costa Rican officials said. Concentrations above 50% are considered lethal.

The former New York Yankees outfielder's 14-year-old son died on March 21 during a family vacation in Costa Rica.

After Costa Rican authorities announced Miller Gardner’s cause of death, a doctor explained the likely tragic circumstances

Miller Gardner—the late 14-year-old son of former New York Yankees outfielder Brett Gardner—died of carbon monoxide poisoning, Costa Rican authorities said Wednesday. The announcement comes 13 days after Miller's death during a family vacation,