Chances are, it is the grandfather doing it… Him blaming you for her actions, to pull the light off him.
Or…
She was/is not, nor has she ever been molested, and just being a typical curious kid, and they know that, and are keeping the kid away from the obvious cookie-jar… (you)
Leave it be, or you will only get yourself in trouble. (If he is molesting her, are you prepared to be killed by implying it to him/her?)
That is called a dangerous situation, stop thinking with your dick, which is what you are doing… someone took away your dirty magazine… (The girl rubbing your ego-hope.)
She is a girl, looking for attention, and you are feeding her, and possibly going to get her in trouble. (She obviously has a big mouth if someone-else "thinks you may have done something with her"… Even if you didn't, that is how innocent people get put in jail, for doing nothing, because a kid will take that attention, that sympathy, that "I didn't lie!" to their grave, and not give two fucks about you…