A baby was found dead after her grandmother cut her throat with a power saw, Chicago police said.
The 52-year-old allegedly used a circular saw to attack the child – identified as Rose Herrera - because she would not stop crying.
Police were called to a building in the city's West Side at about 9.40am on 9 March.
The woman had reportedly tried to shove something into the baby's mouth to quieten her down.
She was taken to Mount Sinai Hospital with self-inflicted wounds after trying to commit suicide where she is being held under police custody.
Chicago police have now launched a "domestic-related murder investigation".
Illinois Department of Children and Family Services said it was investigating the case and said it had no prior contact with the family.
Neighbours told ABC7 a couple lived in the home with two grown-up daughters who each had a baby.
"When I came out I heard a young lady in front of the door, and she was crying, 'When am I going to see my mom?' or something like that," one neighbour told the TV station.
A friend of the child father's, Ben Llamas, told the Chicago Tribune: "He adored her [the child] and was in shock."