What should I do when I suspect sexual abuse to my neighbors in Honolulu?

I have good friends from my neighbor, and she is 7 years old.
She has shared with me that her uncles touch her private place and he tried to do it even further.
She was not aware of sexual abuse as she may be too young to understand it.
I think the first thing I should do is to talk to her parents, but anything I can do for her to add to it?