Reginald Williams of Brooklyn was arraigned Sunday on murder, manslaughter and assault charges in the death of Aiyden Davis. The boy was found unresponsive Friday inside the couple's apartment.
Williams pleaded not guilty. His lawyer says some of Williams' statements to police were taken out of context.
The boy's mother, Teresa Taylor, was not home at the time. But prosecutors say she admitted she also beat the child earlier in the month. She was arraigned on charges of assault, criminal possession of a weapon and endangering the welfare of a child.
Her lawyer says she was a good mother.
The medical examiner says the cause of death was blunt impact injuries to his head, torso and extremities.