Just a few questions

Great movie, very enjoyable seeing her kill the guy and the kid in the end, and interesting to watch. Sound quality wasn't the best so i am sorry if some of this was explained in the movie and I failed to hear it.

1. Who was the girl they kept with the dogs? If daughter, why?

2. Why did the sister and the mother tell the father that they caught the son touching the girl and masturbating, when the sister actually caught him also physically torturing her? He cut off her nipple, didn't he? Why was that not mentioned (it probably wouldn't make a difference to the father, but I still found it curious.)

3. At the beginning we see the woman having a baby. Should we assume she had a baby and it probably died while she was away - which would explain her interest in Peggy? Or is that actually the end where she has this dude's kid?

4. Peg was pregnant by her father, right?

Finally, just an observation, but the teacher should not have said anything as soon as the father insisted for the brother to also stay and listen. She should have just pretended she was there to check on her health. For someone well intended, she could have assumed she'd be putting Peg in trouble if she thought about her fear and fathers odd behavior.