State is painting a very nuanced theory that is more specific to MT than might be evident. Yes they have to prove a murder. And no they don’t have to prove motive. But I see this weird plot line developing about MT’s narcissistic mindset. The theory that MT wasn’t really involved “but should have known” and implicated herself after the fact is one way to hold her responsible on some level. But with her fixation on sex before and after the murder 1) making up or fantasizing sex in shower right before sending FD off to murder 2) tempting sex during the murder via emoji and 3) making up sexy time cleaning the Tacoma - I think in her head SHE thinks he is killing for HER. And in her narcissistic head - she finds that sadly arousing. It emboldened her, she encouraged FD, and was all-in on the plan for her own self-aggrandizing motive that is distinct from FD’s motive (just to get out of the divorce/custody). Look how fast he moved on from her.