An autopsy later showed that the 1-year-old died of head trauma, authorities said.
An investigation identified Dixon, who was described as the "roommate/boyfriend" of the child's mother, as the suspect, the sheriff's office said.
No details on what led authorities to suspect Dixon were immediately provided.
Dixon was charged with murder and first-degree cruelty to children. He was being held without bond at the Bibb County Law Enforcement Center.
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