Police are investigating the death of a woman and "serious" injuries to her daughter.
The child, believed to be about three years old, was taken to hospital after the incident at a block of flats in Maidstone, Kent, in the early hours of Friday.
Forensic teams cordoned off an area around the flats at Hawley Court, in London Road, Maidstone, while they secured the evidence.
A Kent Police spokeswoman said the girl was being treated for "serious" injuries, which appeared to be multiple, at a hospital in Maidstone.
She could not reveal the nature of the child's injuries but it was not thought firearms were involved.
Police have confirmed they are not looking for anyone else in connection with the incident.
A spokesman said they were not yet able to release the identities of the woman and child.