I want to hear your theories about the missing girl and why Kim Do Ha's sentence sounds like a lie
I think FL hears lie when people believe they are lying. If someone believes that he has killed someone and blames himself for that, she will register it as lie if he tells her he didn't kill that person.
https://www.youtube.com/watch?v=XI7p_3mHt
https://www.youtube.com/watch?v=9k9U4aXkbtQ
https://www.youtube.com/watch?v=jxuwXiFguHQ
https://www.youtube.com/watch?v=5TeAGW0p3gE