also, some advice. I suggest you go over the difficult dialogue more then once. I takes some time but you will learn alot from it. I’m guessing you missed some stuff in this episode because you had trouble with the dialogue. I’m by no means great at Japanese, and i’ve got some serious problem with series like 図書館戦争 but Himitsu is quite easy, there’s some not alot of technical nonsense like in many mech-series and very few made up words and wierd loanwords, so it’s a great series for picking up new vocabulary :)

Here’s the part where they talk about why she didn’t kill the father

6.05 キヌコの服には血のようなものがついていました
そのことを知られるキヌコは。。口封じのために家族を皆殺しにしたんじゃないかと。。僕が思うんです。　

なら、キヌコはなぜ父親を殺さなかったんだ？
父親に全ての罪を着せるためです。
キヌコは知ってたんです。つゆぐち(name of father)が自分を愛していること。

Rei: I don’t think anything was mentioned about Maki’s past this time.

Kinoko’s father abused her sexually. He was in love with her. Kiniko came to grow up to despite and loath men, and started luring men away to that ramshackle old house to kill them. Her father eventually figured out that Kiniko was killing men, and Kinoko also figured out that her father had found out about her activities.

She knew her father loved her so much that he would do anything for her. So she killed her own family to get her father to take the blame. I don’t think she even had a reason to kill her own family, it was just a method of getting to her father and hiding her own murders.

Kinoko was a cold-blooded killer, created by the actions of her own father. I don’t think the father realized just how badly he was played until he was sitting on deaths row, writing that letter.

This episode looks intriguing, the screencap with the skeleton makes me think that this episode will be different from the earlier ones. Can’t wait to see this get subbed.