Authorities are searching for Akeem Page of Reading on involuntary manslaughter charges.
Berks County District Attorney John Adams says Page was upstairs with the baby's mother Sunday when a rifle he was handling discharged. Adams says the bullet pierced the floor, causing a fragment to strike the baby in the head.
Seven-week-old Michael Johnson died Tuesday.
Adams says the shooting occurred at a house Page shared with the baby's aunt. He says there is no evidence the shooting was intentional.
Adams says the rifle has not been recovered and Page remains on the lam.
Involuntary manslaughter carries a term of up to five years in prison.
Anyone with information about Page's whereabouts is asked to call Reading Police at (610) 655-6111 or Crime Alert Berks County at (877) 373-9913.
The coroner is withholding a ruling regarding Johnson's manner of death until the autopsy is complete.