Yes. Either there WERE signs of malfeasance/evil that we missed (whoever 'we' are), or they were plain in sight all along had 'we' just paid attention. The theory that normal folks like you and I just don't all of a sudden one day "snap."
I think part of why it's hard for the average person to subscribe to the "just snapped" theory - people snap apropos of nothing whatsoever, is we don't really hear about it. We just hear- overandoverandover- "Oh, we are so surprised John or Susie Q did that. There's NO way. He wouldn't hurt a fly...." said into TV cameras or quoted after a horrific murder. "That never happens in this town."
It gives us a sense of control over our world & surroundings to think we can spot the predators. I like to think I get a vibe from people like that in person, & I do sometimes. I do sense the people to give a real wide berth to. All I know about CW's picture is I think he's a punk. I would have thought that had I randomly run across his FB.
Trigger warning (on a crime site, lmao)
A friend in CA had a friend who was murdered by her boyfriend. He chased her thru the house, pulling big clumps of her hair out, then stabbed her to death. It was an argument. Before that, he was a dream guy, no signs, always nice, respectful, decent. He called his son and simply stated, "I did something really bad..." My friend couldn't get over it, how the guy had no violence in his background whatsoever.
So maybe that's where the fan fiction evolves from. We just want to believe, we want to feel safe. But we are never truly safe. As a woman, the best I can do is extricate myself from any situation I think there's a remote chance of something about to go down. For Mollie, however, all she did was go out for a jog. That's it. I could walk out to my mailbox this afternoon, & my crazy next door neighbor could dislike something about my t-shirt, & go off. You never know.
edit: is there a branch in psychology that studies or has theories accepted by mainstream science that does subscribe to the 'snapped apropos of nothing' theory? How seriously is it taken?