This was my exact opinion. For whatever reason I will never understand, NK did not appear in the interview to be particularly devastated for the murder victims nor horrified what she had to have just learned that very day or late the night before. The interview was on the 16th. He "confessed" to where he dumped the bodies only the very night before this. IMO
And one more thing. People here have criticized NK for her vocabulary, her grammar, especially in view of her college ed.Her looks were criticized.
In real life, it does not matter.
I ordered Amber Frey's book and I am reading it.
Amber is a totally different person. She does not have higher education, does not come f from a good family and is not especially beautiful. She is very devout, but I found her interpretation of religion naive. Her language is trivial. And yet... in her life, which was not easy, Amber tried to extract goodness out of everything, her religion, experiences with people, her hard work, and finally, her daughter.
It was not her fault that she, a single mother tired of being a masseuse, fell for "a solid", like she thought, guy, Scott P. After she realized that he was a liar (and possibly, a murderer), she felt compassion towards the humans of whose existence she never had known (Laci and her unborn son). She thought, "he would have been born on my birthday". She was pretty harsh with Scott in her taped interviews. She saw through his lies. She was only in her late 20-es, but so more mature than N.K.
Here is what Amber Frey said in her interview of 2015: "We're doing good. I don't regret anything. As crazy as it sounds as what came out and whatnot, I would do it all over again because it wasn't about me. There was a missing woman carrying a child that if I had something that would help, without question (I would)."
Scott P. is a horrible person, but at least the woman he fell for, Amber F, is a wholesome human being.
In contrast to Amber and her personality, it appears that Shanann, Bella and CeCe were killed for a shallow relationship.