A woman reported her grandson to the Florence Police Department after she saw bruises on a 2-month-old child in his care.
Police then found injuries to two older girls, both under the age of 3, who also were being cared for by Billy Crunk.
Crunk told police he'd been the sole caregiver following the arrest of the children's mother a month ago.
The Department of Human Resources has intervened.
The infant was found to have suffered internal injuries.
Crunk faces multiple charges, including willful abuse of a child and simple assault.
He was booked in the Lauderdale County Detention Center on $30,000 bond.