A masked teenager armed with a bag of knives who stabbed a shop assistant to death as she stacked shelves in her store faces detention for a "very, very long time indeed".
Ethan Mountain, who was wearing a horror mask and had his hood up, launched a "50 second" attack on Joan Hoggett in the One Stop Shop at Fulwell, Sunderland, and left her with 29 knife injuries which caused damage to her heart, lung, arteries and intestine.
WATCH: Family of Joan Hoggett make plea over knife crime as they urge those with mental health issues to seek support
The attack, which happened shortly before closing time on September 5 last year, led to "catastrophic" blood loss, which sent the 62-year-old grandmother, from Grindon, into cardiac arrest and resulted in her death.
CCTV footage shows killer Ethan Mountain in moments before and after he stabbed Joan Hoggett to death
Mountain left a blue Nike holdall at the scene, which contained a sheathed Hibben custom knife, a sheathed samurai sword, two sheathed machetes, a hunting knife, a hinged knife, clothing, and a document with his name on.
The 19-year-old, of Heaton Gardens, South Shields, who is currently detained in Rampton top security hospital, admitted manslaughter on the grounds of diminished responsibility.
READ MORE: Mental health chiefs carry out internal investigation into Ethan Mountain case
He had been on trial at Newcastle Crown Court, where prosecutors claimed the killing, which may have been part of a botched attempted robbery, was murder.
But Mountain's legal team claimed the teen was suffering an abnormality of mind at the time of the killing, which impaired his responsibility for it.
Prosecutor David Brooke QC said today it is now accepted on both sides that Mountain is a paranoid schizophrenic and "very ill".
READ MORE: CPS explain why Ethan Mountain was cleared of murder
Mr Brooke said: "This is one of those rare cases that should not proceed any further.
"In the circumstances, notwithstanding this killing, which we all acknowledge was a horrific one, the Crown take the view that the proper course here is not to seek a conviction in respect of count one (murder)."
Trial judge Mr Justice Butcher order the jury to deliver a not guilty verdict in respect of the murder charge.
Mountain will be sentenced for manslaughter next Friday.
His barrister Leonard Smith QC said the teen could face a period of detention or be given a hospital order, which would mean The Home Secretary would have to approve his eventual release.
Medical evidence will be heard at the next hearing, before Mr Justice Butcher decides on the appropriate outcome.
Mr Smith apologised to the family of Mrs Hoggett for his application to adjourn the sentence, while the medical evidence is gathered.
He added: "I have complete and genuine sympathy for the family of Mrs Hoggett.
"I know me making this application will be causing further pain to them."
Listen to 999 call friend of Ethan Mountain makes to police after he stabbed Joan Hoggett to death
Mr Smith said, whatever the outcome, Mountain will be detained for a "very, very long time indeed".
Mr Justice Butcher agreed to adjourn the case until next Friday but added: "I am very reluctant to prolong the agony for the family in this most distressing case."
The court heard Mountain had been diagnosed with ADHD when he was just 12 and was detained in a psychiatric hospital between June and August 2017, where he made chilling revelations about his thoughts.
Mountain had told staff: "Everyone thinks that I am a good person, that's because of the ability to charm people and they trust me.
"You may think that's scary, someone having the thoughts I am having, to trick someone into thinking I'm a nice person when inside I want to seriously hurt them."
Mountain, who said he started taking cannabis at age 15 but cut back because he experienced "profound hallucinations" claimed to have harmed animals in the past and told medics: "Someone will get killed and then I will get arrested."
READ MORE: Senior police officer left shocked by "absolute randomness" of attack
The court heard Mountain was on a "low dose" of anti-psychotic medication when he was released from the psychiatric hospital in August 2017, a day before his 18th birthday, and started drinking vodka, heavily.
Mountain claimed he had stopped taking his prescribed medication "about a week before" he attacked Mrs Hoggett and was due to see a psychiatrist the following month.
During interview after the attack, Mountain told a psychiatrist he had been hearing voices and had had an argument with his mother just before the killing.
He added: "She was concerned I was drinking too much, I was concerned that the doctors would throw me back in hospital.
"The voices were saying I would be crazy and I would be sectioned."
Mountain said he had limited recollection of the actual attack on Mrs Hoggett.
He told a psychiatrist: "I can't remember physically doing it, I just remember walking to the shop, thinking people were talking about me and then I was coming out of the shop, covered in blood.
"I knew I had done something wrong, I went to the park and began self-harming."
Mr Brooke Qc had showed the court shocking cctv footage that captured Mountain leaving his home in South Shields, walk to East Boldon Metro station and board a Metro train to Seaburn, carrying the rucksack.
After leaving the Metro at Seaburn station, Mountain walked to the shop and appeared to pause for around a minute, and put on the mask, before he entered the store.
The video recording from inside the shop showed Mountain, wearing a hood and mask, approach Mrs Hoggett as she worked in one of the aisles.
The killer then launched the attack, appeared to pause, and then continue the violence before leaving.
Mr Brooke told the court the "matter was over in about 50 seconds".
The court heard Mountain had turned up at a friend's house in the hours after the killing, wearing bloodstained clothing and with superficial cuts he may have caused to himself.
He told the pal he had "stabbed someone" and said he had been "seeing people and hearing stuff".