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When we come back, the families battle to save their daughters, to get them help, and to get them a chance to one day come home. But will they be sent away for years after what they did in the woods? Their fates revealed when we come back. It has been more than three years now since that horror in the woods in Waukesha, Wisconsin. And now a community torn.

As brutal as the attack was, what do you do with two girls who were just 12 years old when they did it? Morgan Geyser and Anissa Weier are now preparing to be tried as adults, facing the possibility of decades in prison.

As brutal as the attack was, what do you do with two girls who were just 12 years old when they did it? Morgan Geyser and Anissa Weier are now preparing to be tried as adults, facing the possibility of decades in prison.

Both girls plead not guilty by reason of mental disease or defect. The girls will be tried separately. Anissa's case is first. And just days before her trial, she strikes a deal with prosecutors, pleading guilty to a lesser charge of attempted second-degree intentional homicide.

Both girls plead not guilty by reason of mental disease or defect. The girls will be tried separately. Anissa's case is first. And just days before her trial, she strikes a deal with prosecutors, pleading guilty to a lesser charge of attempted second-degree intentional homicide.

But as part of that deal, Anissa will now stand trial so a jury can determine if she should be sent to prison or to a state mental institution instead.

But as part of that deal, Anissa will now stand trial so a jury can determine if she should be sent to prison or to a state mental institution instead.

Now 15 years old, walking into court, Anissa's attorney, Joe Smith, acknowledges that she attacked her friend, but argues she is not criminally responsible because she was under the spell of a delusion. The prosecution paints a starkly different picture of a calculating 12-year-old.

Now 15 years old, walking into court, Anissa's attorney, Joe Smith, acknowledges that she attacked her friend, but argues she is not criminally responsible because she was under the spell of a delusion. The prosecution paints a starkly different picture of a calculating 12-year-old.

The defense calls family members, friends, teachers to the stand to testify that they never knew Anissa was struggling with mental illness, starting with her father, Bill.

The defense calls family members, friends, teachers to the stand to testify that they never knew Anissa was struggling with mental illness, starting with her father, Bill.

But it would turn out the centerpiece of Anissa's defense would be testimony from three mental health experts. Had you ever seen a case like this before?

But it would turn out the centerpiece of Anissa's defense would be testimony from three mental health experts. Had you ever seen a case like this before?

Dr. Melissa Westendorf was one of the court-appointed forensic psychologists who evaluated Anissa.

Dr. Melissa Westendorf was one of the court-appointed forensic psychologists who evaluated Anissa.

And it was Morgan's mother, Angie, who told us she believes her daughter actively hid her delusions from those around her.

And it was Morgan's mother, Angie, who told us she believes her daughter actively hid her delusions from those around her.

And Dr. Westendorf says there also may have been something uniquely compelling to these already vulnerable minds of Morgan and Anissa about the way Slender Man is presented online.

And Dr. Westendorf says there also may have been something uniquely compelling to these already vulnerable minds of Morgan and Anissa about the way Slender Man is presented online.

And the doctor says with Anissa, there was something different at play. Remember, it was Morgan who was diagnosed with schizophrenia. Dr. Westendorf then diagnosed Anissa with what's called a shared psychotic disorder, saying that Morgan's schizophrenia, when paired with both of their delusions about Slenderman, would create a perfect storm, luring Anissa in too.