The knife used in the attack on the schoolgirl PA

A schoolgirl obsessed by serial killers, school shootings and Batman villain The Joker has been found guilty of the attempted murder of her best friend.

A jury heard how the pupil, aged 14 at the time, lured her victim to a quiet corner of their Hampshire school grounds with the promise of giving her a present before stabbing her with a kitchen knife.

The defendant, now 15, who had researched fatal stab wounds, denied intending to kill her victim during the 25 April attack but had admitted wanting to hurt her.

The trial also heard that, the night before the attack, she had a cut a "Chelsea grin" on her face to emulate Heath Ledger's The Joker from The Dark Knight Batman film as she intended to enter an "insanity plea" if she was arrested for a crime.

She had previously pleaded guilty to unlawful wounding and possession of a bladed article on school premises.

She closed her eyes as the guilty verdict was announced at Winchester Crown Court on Wednesday (12 October) and fought back tears as she was led from the court. The judge, Justice Fraser, adjourned the case for sentencing on a date to be set and ordered a psychiatric report and pre-sentence reports to be prepared.

He told her: "You are going to have to come back to be sentenced in a number of weeks. There are certain reports I need and one of them is a psychiatric report."

The jury of seven women and five men took two hours and 45 minutes to reach its unanimous verdict.

The trial heard how the defendant, who cannot be named due to her young age, lured her victim to a quiet corner of the school with the promise of giving her a present. But after she asked her friend to close her eyes, she pulled the knife out of her bag and lunged at her. The friend escaped with a minor injury to her chest because she opened her eyes at the moment of the attack and managed to pull away and run off.

The court heard that, during the previous night, the defendant had researched fatal stab wounds to the heart. The girl had also admitted to being fascinated with serial killers and had even produced a fashion GCSE project based on American murderer Ted Bundy.

The court heard how she had also planned to slit the throats of her mother and brother while they slept and had produced a journal, which she later burned, with a plan for a school shooting which included a "kill list" of 60 people.

The Dark Knight
Heath Ledger playing The Joker in The Dark Knight (2008) Warner Bros

The defendant said she had planned to do something "sensational" so that she would "stand out" from others and because she was not interested in having a 9-5 life "mapped out" for her.

James Newton-Price QC, prosecuting, said: "The defendant was for a period of time obsessed with serial killers and school shootings and the notoriety that attaches to those who commit those crimes. She had even at one stage prepared what she described in her own words as a 'kill list' of those she didn't like at her school. She had even thought about how to kill her own mother and brother and she discussed how to do so in the two or three weeks leading up to an incident in which she stabbed her friend at school.

"It seems that she decided to kill her best friend; she had already researched online how to kill swiftly and effectively with a knife."

She had discussed her plans with another friend which she said was a fantasy "to see how far she could push" her ideas, but the court heard that she had sent this friend a message saying she would carry out the stabbing on the morning of the attack.

The defendant said she had chosen her friend as her target because she felt "uneasy" about her after fake social media profiles were set up in her name the previous summer. The victim denied any involvement.