During the first trip to the hospital, doctors thought the child might have suffered a seizure due to fever from a double ear infection.
But after the Sep. 7 hospital trip, a CT scan showed bleeding in two parts of the child's brain.
Each time the boy suffered a seizure, the baby had been alone with Huettl.
Doctors' tests showed bleeding in the head that pointed to child abuse. The tests revealed both pre-retinal and retinal bleeding. The doctor said that's a common sign in a baby that's been shaken or suffered a severe blow to the head.
Doctors told police it's possible the child could have developmental issues due to his brain injuries.
Huettl was convicted of domestic battery in 2013.
He faces more than 40 years in prison if convicted. Huettl is due back in court in March.