The defense continued to call witnesses on Thursday morning in the trial of 15-year old Anissa Weier.
Weier is one of two suspects in the May, 2014 stabbing case often referred to as the "Slender Man stabbing."
According to prosecutors, Weier and her friend Morgan Geyser stabbed classmate Peyton Leutner 19 times and left her in a Waukesha park.
After the girls were taken into custody, Weier and Geyser told investigators they were trying to please the fictional horror character Slender Man.
During three and a half days of testimony, Weier's attorneys have worked to show the jury she was a lonely 12-year old struggling with mental illness and her parents' recent divorce at the time of the stabbing.
On Thursday, Weirer's attorneys called her former teacher at Horning Middle School, Jeffrey Taege, to the stand.
Taege said he remembered Weier as a "typical" middle school student.
He said she was slightly less mature than her peers when interacting with classmates. But Taege also testified that Weier was more mature than her fellow students when interacting with adults.
Taege also said he was unaware that Weier had discussed the Slender Man character or the Creepypasta Wiki - where stories about him can be found - with anyone in class.
The defense then called Dr. Gregory Van Rybroek to the witness stand.
Van Rybroek, the Director of the Mendota Mental Health Institute, told the jury how the adolescent brain is not fully developed, and often changes between someone's teenage years and their 20's.
Van Rybroek, who possesses a law degree, is also a professor of psychology at UW-Madison.
He said he met with Weier more than two years after the stabbing and, in his opinion, she was delusional during the attack.
The doctor said an example of delusion is a man believing he is the King of Spain, and refusing to change his mind when presented with the real King of Spain.
"I thought she had a fixed and false belief she shared with her friend Morgan so we call that a shared delusion," Van Rybroek said. "At the moment of this terrible, tragic event she was confused and convinced that something real was going on with this very strange character."
"I think at the time she knew it was wrong, she knew the difference between right and wrong, but even so she could not stop herself at the moment that mattered most," he testified. "She was convinced this character who we know now to be a fantasy, was not a fantasy but was real - in her mind."
Last month, Weier pleaded guilty to attempted, second degree intentional homicide in connection with the stabbing. The state recommended a 10-year prison sentence, although the judge can sentence her to up to 25 years.
As a result of Weier's guilty plea, the jury in her trial will not have to determine if she participated in the stabbing. Instead, the jurors will be tasked with deciding if Weier is mentally ill.
The burden of proof rests with Weier's lawyers to prove their client is mentally ill and not legally responsible for the stabbing.
After the defense has finished presenting its case, the prosecution could choose to argue Weier's attorneys failed to prove their case and not call any witnesses.
Both sides would then present closing arguments before turning the case over to the sequestered jury.
If the jury's verdict comes back in the defense's favor, Weier is facing at least three years in a mental hospital instead of the sentencing options agreed upon as part of her plea deal.
Geyser is expected to go on trial next month.