A troubled Perth teenager who tried to kill a "trusted" teacher told the victim she had "a good surprise" for her before lunging at her with a 32-centimetre knife with "a calm and intent look on her face", the Perth Children's Court has been told.
The girl, who cannot be identified, was 14 years old in November last year when she brought the knife to Willetton Senior High School from home with the intention of using it to fatally stab the 55-year-old victim.
State Prosecutor Brad Hollingsworth told the court at the time the girl was dealing with sensitive and complex issues, including episodes of self-harm and suicide attempts.
He said the teacher, with whom she had a good relationship, had been supporting her and her family.
However, in the weeks leading up to the attack, the girl had been having online conversations with a friend on the social media platform Discord, discussing plans to stab the teacher.
'I can kill the witnesses'
Some of those messages were shown to the court, including one where the girl said: "I can stab the teacher and kill the witnesses."
In others, she said she had read five articles on stabbing people and goes into detail about what she can do, including targeting the armpit to sever an artery that "can cause instant death".
Mr Hollingsworth said the girl also told other students what she was going to do but they did not think she was serious.
Because the girl was subject to bag searches at school on the morning of the attack, she gave the knife to the friend to hide before she was given it back at recess.
She also told three other students, "I'm going to stab [the teacher]", "everything is going to plan" and "I'm going to go through with it".
The girl then went to a small interview room to meet the teacher.
At first, they chatted about classes, Halloween, and the name of a baby echidna.
Mr Hollingsworth told the court the girl then said: "Miss, I've got something for you."
The teacher asked whether it was good or bad, to which she replied: "It's a good surprise, Miss."
Girl had 'intent to kill'
Mr Hollingsworth said by that time, the other students had alerted staff to what was happening and one of them tried to get the teacher's attention through a window.
"As the victim stood up, [the girl] lunged at her … she looked her in the eyes and had a calm and intent look on her face," Mr Hollingsworth said.
While the court heard the girl managed only to inflict a small wound, Mr Hollingsworth said at the time she stabbed the teacher, "her intention was to kill her".
The girl then fled the school grounds but was arrested later that evening.
Mr Hollingsworth said that during a search of the girl's room at home, police found a piece of paper with black scribblings on it that included the words "murder" and "on Monday".
He said while the girl later told police she knew what she did was wrong, Mr Hollingsworth said he was not in possession of any evidence why she chose the victim.
Teen had 'special relationship' with teacher
In his submissions, defence barrister Anthony Elliott said the girl was sorry for what she had done and the consequences for the teacher and her family.
At one point, president of the Children's Court Hylton Quail questioned why the girl had targeted the teacher, saying, "she had a special relationship" with the girl and trusted her.
"That trust was betrayed," Judge Quail said.
Mr Elliott said he also found it very difficult to find a reason.
"She was [the girl's] crutch and her saviour"
"[The teacher] was someone who was dedicated to the task of helping her and was helping her."
Girl had been experiencing delusions
Mr Elliott said at the time, the girl had mental health issues, was in a state of emotional confusion and had an emerging personality disorder.
"This was a child who was in a mire of irrationality and who was driven by her irrational thoughts," Mr Elliott submitted.
He also said the girl had been starting to have delusions and was seeing "dark, shadow-like monsters".
Mr Elliott said the mental health issues reduced the girl's moral culpability for the crime.
Plan was 'pre-meditated, meticulous'
In response, Mr Hollingsworth described the girl's crime as a pre-meditated, meticulous plan to murder a teacher who "had bent over backwards" to help the teenager with her emerging issues.
Mr Hollingsworth described a letter written by the girl for the court proceedings as "glib" and "superficial", saying she appeared to focus on her own issues and had the attitude "I wasn't well then, but I am now, so let's move on".
"The lack of empathy is frankly disturbing," he submitted.
He also described the girl as "potentially dangerous", calling her crime "chilling", "disgraceful" and "violent".
The court heard parts of a victim impact statement, in which the teacher said she was "struggling at all levels" and doesn't know if she can return to teaching, her profession for 30 years.
Mr Hollingsworth said the need for general deterrence and to protect teachers meant a lengthy term of detention should be imposed.
Judge Quail told the girl, who pleaded guilty to a charge of attempted murder, the offence was too serious for anything other than a term of juvenile detention.
He remanded her in custody, saying he wanted to see how she goes in custody before determining the length of the term.
She will be sentenced at the end of the month.
The girl's co-offender, who was 13 at the time and pleaded guilty to a lesser charge, is due to be sentenced next week.
