I think people are trying to find “predictors” or indicators of the future crime. And in this regard, there are none. When I looked through these poorly made videos, there was nothing that could tell me that in less that a year, this man would commit a heinous, planned, murder.
Sadly, unless there is a major history of prior violence, no one can foresee nor foretell these events.
Arendt’s phrase “the banality of evil”, sadly, applies to this story as well. We can debate whether PF is attractive or not, but he does not look a horrible human being on photos. Whatever might be said about KK’s looks, to me, she appears perfectly normal. Worse, I can imagine her being a likable nurse.
This is probably the scariest part of all. Another scary part - PF did not stand to gain from KB’s death. Neither financially, nor in any other way. In fact, she was trying to do everything possible to make their situation normal. And he had full access to the kid. There was no dire need to kill her. Even in CW’s case, at least, there was grave financial debt. Here - nothing!