NEWNAN, Ga. -- A Newnan dad is charged with killing his infant son after requesting to spend the night with him unsupervised for the first time.

The incident happened over Father's Day weekend when police said 30-year-old Christoper Halver-Gene Hansen asked all for all of his children to spend the night with him. This would be the first time 4-month-old Saxton Livingston would sleep over at his house.

Early morning on Monday, June 17, Hansen would call 911 and say his son had choked on milk and was unresponsive. Hansen described him to the 911 operator as being "limp" and making "gurgling noises."

Saxton was taken to Piedmont Newnan Hospital but the staff didn't find milk in his throat or mouth. He was then airlifted to Children's Healthcare of Atlanta at Scottish Rite where he stayed until he died on July 25.

Now, Hansen is charged with his son's murder. The alleged details above came from his arrest warrant outlining why he is charged with murder and cruelty to child in the first degree and second degrees.

Doctors told police the 4-month-old suffered "abusive head trauma which resulted in a massive brain injury."

During the month he spent in the hospital, Saxton reportedly suffered from "large subdural hematomas, subdural hemorrhage, pulmonary hemorrhage, bilateral multilayer diffuse retinal hemorrhages, shock and hypoxic ischemic brain injury caused by "abusive head trauma." During this time he had "minimal brain activity," according to doctors.

Saxton also tested positive for marijuana. Newnan Police said they also reported smelling "smoked marijuana" inside of Hansen's home at the time of the initial incident.

In his autopsy, the coroner found blood in his brain, a non-accidental brain injury and described his brain as being "grossly very small."

Hansen is being held without bond in the Coweta County Jail.