stand. >> what did you know of ashley having a mental illness? >> i knew that she was on medications. we spoke pretty in depth about that. >> reporter: but even with medications, the friend testified, ashley had trouble controlling her emotions. >> what kind of mental health issues, uhm, did you observe ashley fallis to be going through? >> depression, mood swings, impulsive behaviors. >> reporter: in fact, the defense argued ashley was so depressed the summer before she died, she wrote this letter to tom. >> "i have so much pain on the inside i can no longer take it. i'm sorry to do this to you and the kids, but i find myself not even liking my children." >> reporter: "every day is a chore with them and you. i have to pretend to be happy. i have to pretend to be someone i am not. please make sure you raise the kids to continue to go the school we have chosen.