Police said this appears to be a tragic accident and that the mother drove to the hospital for work and left the child in the car. By the time she returned, it was too late.
The baby was in the car for nine hours, police told FOX 13. Temperatures outside were 70 to 75 degrees, and the car was heated up to over 100 degrees that day.
Police said the woman is a social worker with the hospital.
No charges have been filed.
The incident is still under investigation.