>> anissa weir. >> morgan seemed like she was very calm. very relaxed. she's at a police department, and she's covered in blood. and this is like a normal day for her. >> what's your name? >> morgan. >> reporter: you can hear morgan ask what's happened to peyton, using her nickname, bella. >> is she dead? >> i don't know. she was taken to the hospital. >> what? i was just wondering. >> it didn't seem like it really concerned her too much if she was dead or e. >> reporter: the dectectives red the girls their rights. >> here in the state of wisconsin a child can be interrogated without the presence of their parent or guardian being in the room. at that time, i did not know that. >> we find people are more truthful when they don't have their parents present. >> this is to get me arrested, isn't it? >> reporter: the interrogations last for hours. >> make yourself a little more comfortable here. >> i have a daughter that's almost the same age as her. like she could be my daughter, but then she started saying things that were really very eerie, even coming out

anissa weir, sitting in that courtroom, shaking. >> has the jury reached a verdict? be sent. >> anissa weier was found not guilty by reason of mental disease or defect. >> in the end, the jury decides she should be committed to a state mental institution rather than going to prison. >> with that, i will order that she be committed to the department of health services. >> a late-night verdict in the slender man trial. the decision, not to send anissa weier to prison. >> their decision was humane. and the actions of a 12-year-old didn't deserve the harshest punishment. >> age was everything. if you're an adult, when you say you didn't understand right from wrong, that's an argument that almost never succeeds. but when you were 12 at the time it happened, you've got a much stronger argument. >> reporter: but it's up to the judge now. the judge will decide how long she'll be sent away. >> we argued strongly for 25 years. >> miss weier, do you want to say anything? >> i know that nothing i say is going to make this right, your honor. and nothing i say is going to fix what