I think there was a clue in her saying she found her parents suffocating and how her mum was lecturing her and she didn't like it. It seemed a deeply personal thing to be sharing with someone (Dr NN) who I don't think she'd known that long and was a work colleague. Which made me think it affected her and made her angrier than she let on.
When younger, I had a friend who is a bit like LL, in that she is the only child of much older parents and also used to feel suffocated. Because she was considered a miracle baby given her mum's age, they were extremely overprotective. And like LL she complained about it but didn't take space from them (did the long holidays, constantly messaging/calling etc). She wasn't a killer but my god, she was bitchy, controlling and never took responsibility for anything. She once snubbed a girl very obviously and was then very shocked when this girl didn't invite her to her bday party - like she couldn't understand her behaviour caused it. She also tried to sabotage another friend's relationship because she fancied the guy - and couldn't understand why the friend wanted nothing to do with her. We all cut her off eventually but it took a while to fully realise how manipulative she was. Because she looked petite and cute, had a good job, softly spoken, seemed completely normal in every way! Last I heard she got married but ended up cheating on her husband. I just think she had zero empathy/compassion or morality, which is surprising given she had a very normal seeming, middle class, quite Catholic upbringing. So some of it must have been nature (just born like that), and her environment must have done the rest.
So maybe LL was just like a more extreme version of this woman..
I also worked with this woman
https://www.grimsbytelegraph.co.uk/news/grimsby-news/mum-who-dumped-baby-william-563985. She was really nice at work - very driven, friendly and chatty. Good at her job too. We were all shocked when we heard she'd been arrested and then imprisoned for murdering her baby.
Even more shocked when we found out about her husband being a paedophile, who we had met as well. They just seemed entirely normal. Since then I've realised anyone can be a criminal, no matter how normal they seem.
https://www.thesun.co.uk/news/45998...her-student-jonathan-layfield-sinead-connett/