Milwaukee police say the suspect removed the full-term baby from the mother’s uterus “by force,” but did not elaborate.
Authorities say the 33-year-old suspect called police saying she had given birth at home and that the baby wasn’t breathing.
An autopsy and investigation led police back to the suspect’s home where they found the 23-year-old mother’s body in the basement.
The suspect has been arrested but not charged.
Family members said the mother, Maritza Ramirez-Cruz, was due to give birth next Sunday to her fourth child, a boy, whom she and her husband had already named Omar.
Milwaukee police chief Edward Flynn said: “Evidence at the scene indicated that she had been fatally injured there, and that the baby had been removed from her womb by force.
“During the ensuing investigations, detectives determined that the 33-year-old woman was not, in fact, the birth mother of the baby.”
Chief Flynn did not disclose how the two women knew each other but said there was nothing to indicate they had ever met before the day of the attack.
Neighbour Keila Perez said the suspect is godmother to her daughter and has three children of her own.
“From what I know she had a baby, she had baby stuff in there, she has a car seat and everything in there. I don’t know what the hell is going on,” she said.
But Chief Flynn said: “We are confident that we have the person responsible.”