Wednesday 28 September 2022 11:23 AM Perth teacher stabbing: Teenage girl, 15 given reduced sentence: Willetton ... trends now A teenager currently serving time in the infamous Banksia Hill facility has seen her sentence cut short despite attempting to kill her teacher in a plot with a friend. The two female students, aged 13 and 14, stabbed their 55-year-old teacher Colleen Hayes in the armpit in her office at Willetton Senior High School in Perth in November last year. They plotted to kill her prior to the horror stabbing, including discussing where best to stab here to sever an artery through social media. One of the girls, now aged 15, was facing a lengthy sentence but instead was handed three years and one month at the Banksia Hill Juvenile Detention Centre - but could walk free as early as 15 months. The decision for the shorter sentence was made by Children's Court President Hylton Quail, who learned during a recent visit to Banksia Hill children were being forced into lengthy lockdowns due to ongoing staff shortages. A teenager currently serving time in the infamous Banksia Hill facility (pictured) has seen her sentence cut short despite attempting to kill her teacher in a plot with a friend The two female students, aged 13 and 14, stabbed their 55-year-old teacher Colleen Hayes in the armpit in her office at Willetton Senior High School in Perth in November last year A recent Supreme Court ruling found one teenager at the detention centre had been unlawfully locked down for 20 hours on 26 occasions. That same teen had also been confined to their cell for 24 hours on three separate occasions in one week. The 15-year-old girl had spent six days in 'unlawful lockdown' over the past two weeks - which influenced Judge Quail's decision to lessen her sentence. She also didn't have access to proper education or recreational activities while inside Banksia Hill. A recent Supreme Court ruling found one teenager at the detention centre had been unlawfully locked down for 20 hours on 26 occasions The court heard the girl, who was 14 at the time of the stabbing, spent weeks planning the attack with her then-13-year-old friend over Discord. The pair even joked about burning down the school - according to The West. The co-accused, who received a reduced sentence of 11 months for her role in the incident, first suggested the stabbing while the older girl planned the area for the knife wound - reading the armpit was an effective location to kill. The older girl told her co-accused she believed she would spend four to eight years behind bars for the crime, the court heard. The court heard the girl, who was 14 at the time of the stabbing, spent weeks planning the attack with her then-13-year-old friend The stabbing was supposed to occur on November 1 so the girl could celebrate Halloween first. On the day of the attack, the girls rode bikes to school where the older girl revealed to her younger friend she had a knife. The younger girl agreed to hide the blade in her bag, as the older girl had her belongings searched as a result of previous self harm and mental health issues. The court heard three students overheard their conversation and attempted to convince the girl not to act, but they were dismissed. The co-conspirators lured their teacher, saying: 'Miss, I have something for you'. When the teacher asked whether their surprise was good or bad, the teenager replied: 'A good surprise'. The young girls had been planning the attack over Discord - and delayed the stabbing to celebrate Halloween By this time, the three students who overheard their conversation had alerted the receptionist - who then told the teacher to come outside. As the teacher stood up, the teenager attacked her with the knife, stabbing her armpit. The teacher had a 1cm shallow wound - but Judge Quail said there were deep emotional scars as a result of the attack. The judge took into account the 15-year-old's guilty plea and that she was not emotionally stable at the time. He highlighted a psychiatric report that said she was at risk of developing borderline personality disorder. Judge Quail also said she had made 'remarkable' progress in her rehab, referring to a letter she wrote to the teacher she attacked where she described feeling like 'a monster' for her actions. All rights reserved for this news site (dailymail) and under his responsibility