Lincoln County State's Attorney Tom Wollman says he will review the autopsy and other reports before seeking any new charges against 27-year-old Joseph Robert Patterson.
Sioux Falls police identified the boy as Tyrese Robert Ruffin, who died Friday after being hospitalized with severe head injuries. Earlier, police gave an incorrect surname.
Patterson, the boyfriend of Tyrese's mother, was charged last week with aggravated assault and aggravated battery. Prosecutors also are asking that a suspended sentence be imposed for a previous domestic assault conviction.
A message left for Patterson's attorney was not returned.
Peterson has declined to discuss the relationship he had with the boy.
Copyright 2013 by The Associated Press