Animal control officer Robert Lagonera said the Washington Township police officer arrived on the scene in rural Warren County early Sunday to find the fawn was moving inside the mother's body.
Lagonera said Officer Jim Vernon delivered a fawn after performing an emergency C-section on the deceased doe to save one of the two babies inside.
After the officer removed the fawn, Lagonera said he took it home, dried it off and kept it warm while rubbing its chest to help the lungs develop.
"Now I'm running around getting the premature fawn the care it needs," Lagonera wrote in a Facebook post. "No amount of coffee is too much today lol."
The Associated Press contributed to this reporting