The boy, who was detained with his father, died shortly after midnight at Gerald Champion Regional Medical Center in Alamogordo, New Mexico, about 90 miles north of the border crossing in El Paso, Texas.

He was taken to the hospital Monday after a border agent noticed signs of illness, and the medical staff first diagnosed him with a common cold and later detected a fever.

“The child was held for an additional 90 minutes for observation and then released from the hospital mid-afternoon on December 24 with prescriptions for amoxicillin and Ibuprofen,” CBP said in a news release.