That's the scariest thing about psychopaths. They look like people.
A neighbor, a teacher, a priest, a rancher, a nurse... your friend Joe from work...
Looking at them through a wide angle lens it seems obvious something is off, but, if you meet one, engage in conversation, or what have you, it can be easy to miss the forest for the trees.
I'm sure pf's dating profile looked really great. It likely didn't say:
"Handsome Psychopath lives on Franch with mommy, beats animals,
dependent on but hates women, works at separating people from their better judgement, seeking to add teeth to growing collection."