The incident happened last evening when the girl, Jannat, was playing on the terrace, they said, adding it is suspected that she might have lost her balance and fall down.
She was rushed to GTB Hospital where she was declared brought dead.
The girl had come to her aunt's house along with her parents yesterday, they added.
Police is probing the matter if the girl was accompanied by some elders when she was playing on the terrace, they said.