I dont think the little girl does know about rape; it says that the mother of the girl found them in a field, and it appeared that something wasnt right
I'm guessing that the mother's immediate thought was that the two boys had raped her. They probably then went home, where the mother tried to get imformation out of her asking her if she had been raped, and that if she had then she should say because what the boys did was wrong etc, etc
My first thought was to string them up, my second thought was that the girl was lying; i'm now thinking that the mother, as any parent would, was trying to get information out of the girl in order to call the police. In doing this I think she probably put ideas into her head, and words into her mouth. I dont think an 8 year old girl is capable of lying about rape, let alone knowing about it!
Either way, if I had've found the oiks with my daughter and I suspected that they had assulted her, I would have buried them in that field