Adrienne Michelle Bush is charged with homicide by child abuse in the death Friday of Amarie Tre'chelle Thurmond, police said.
On Tuesday, North Augusta investigators arrested Ms. Bush after interviewing her and the child's father, North Augusta Lt. Tim Counts said.
"Once we interviewed the father and we interviewed the mother, she admitted and confessed to actually striking the child with her fist repeatedly on the head, which we believe ... produced the head trauma which caused the child's death," Lt. Counts said.
He said no motive has been determined.
Emergency personnel were called about 11:30 a.m. Friday to Ms. Bush's home in the Breckinridge II Apartments on East Martintown Road and found her holding the infant's body, according to a police report.
"The child was obviously dead," the lieutenant said. The infant was not breathing and was showing signs of rigor mortis when authorities arrived.
Aiken County Coroner Tim Carlton said a Saturday autopsy determined Amarie died of massive head trauma.
The infant's father was likely at the home at the time of the incident, but Lt. Counts said investigators believe the man was busy tending to Ms. Bush's 6-year-old child from a prior relationship and the couple's 2-year-old.
"At this point in the investigation, we don't have any reason to believe he was involved in the child's death, nor do we believe he had any knowledge of (a crime)," Lt. Counts said. No charges are expected against him, he said.
Investigators say they do not know whether Ms. Bush has a history of abusive behavior.
Reach J. Scott Trubey at (706) 823-3424 or firstname.lastname@example.org.