It happened around 4:30 p.m. on October 30 along the 1700 block of Folsom Street.
Action News has learned at least one woman was taken into custody but no charges have been filed.
Police say the 4-year-old fell from the window onto some lawn chairs.
The girl was rushed to an area hospital where she died days later.
It happened just doors from Gordon Atkisson.
"It is shocking. You never want to hear something like that happening in general at all, let alone to a baby or a young child. So, it's shocking and very surprising," he said. "I didn't really know them. I never talked to them, but they seemed friendly which makes this even more shocking."
The woman caring for the child was not her mother, the family told Action News.