Nicholas Prosper, 19, has been sentenced to a minimum of 49 years in prison for murdering his mother, brother and sister in Luton last year
The bodies of Juliana Falcon, 48, Kyle Prosper, 16, and Giselle Prosper, 13, were found at their home in September
After killing his family, Prosper planned to carry out a mass shooting at his former primary school - having chosen a Friday 13th date deliberately
Mrs Justice Cheema-Grubb says Prosper "intended to unleash disaster on the community of Luton" and was "inappropriately cheerful" after being arrested
The court heard Prosper hoped to kill his family while they slept - but after a noisy struggle, he left the flat and neighbours called police
Watch Prosper being arrested here and him buying his shotgun in a car park here
Watch: Teenager sentenced to minimum of 49 years in prison
The prosecutor is now outlining how Prosper told the practitioner that he did not hate his family, but he "wanted to be famous".
He showed the member of staff how he would shoot himself after the school massacre.
After about an hour, the practitioner felt she had heard too much and ended the review they were undertaking.
More of Prosper's confessions are being read to the court. Warning - they continue to be graphic in their nature.
Prosper told the medical practitioner that he wanted to shoot and rape Giselle, but his mum "messed it up" by waking up.
His brother hid in the kitchen and "began pleading for his life" during the attacks.
He outlined his plan to go to the primary school, but said that was "messed up" by neighbours hearing the gunshots.
Cray says: "He wanted to cause the biggest massacre in the 21st Century."
We're now hearing comments Prosper made to a medical practitioner at HMP Bedford, where he has been held.
On 17 September 2024, he whispered to her during a review "I wish I had killed more".
Other comments included:
Two police officers returning to Luton police station from the scene were flagged down by Prosper at about 07:55, Cray says.
During his arrest, he repeatedly told them "it wasn't murder", having shown the officers where the shotgun and cartridges were hidden.
Prosper told officers he had been stung by stinging nettles and his hands were cut, and asked them: "How did you get into armed police?"
Once at the police station at 09:10, he made a number of unsolicited comments in his cell, including "are you capable of what I have done?" and "there was no choice, I had to do it".
Nicola Haseler
BBC News
Prosper had his fingers in his ears while that pre-recorded video of him was being shown to the court just now. He then puts his head in his hands.
Image source, YouTubeProsper uploaded a video online after carrying out the murders
The court is now being told that Prosper uploaded a video online after the murders, at about 06:22.
That video had been recorded the day before, indicating "forethought", Cray explains.
In the video, he referred to The Walking Dead video game and suggested he planned to shoot Giselle in the face.
However, Cray says Prosper was not "solely or even mainly motivated" by the video game. This, he says, is clear due to his research of mass killers.
Blood was found throughout the flat in the form of handprints, smeared blood and airborne blood, the prosecutor says.
Kyle, 16, was shot twice, initially in the kitchen, and suffered slash wounds to his hands, arms and legs.
"[It was] as if he had been using his hands and limbs to protect the vital areas of his body from knife blows," Cray says, adding Kyle suffered more than 100 stab wounds.
"The shot that killed him was to his head and that had been fired at close range."
Juliana's body was found in the hallway and she died from a gunshot wound to the top of her head. The 48-year-old also had defensive injuries.
Giselle,13, was found in the living room, with the fatal shot fired at her face.
"Experts believe that the defendant fired at least seven cartridges inside the flat, Cray continues.
"One of these appears to have been a test firing inside the defendant’s room against a teddy bear."
Nicola Haseler
BBC News
The court has just been shown images of dummies laid out in the same way that Prosper's victims were found.
This captured the defendant's attention - he peered over to look closely at these.
A reminder that as we continue to hear this distressing evidence, there is support available for anyone affected on the BBC Action Line.
We will continue bringing updates as they come from court.
"What the neighbours had been hearing was the killing of Juliana, Kyle and Giselle, starting around 05:00," Cray continues.
He says the forensic scientists who entered the flat found Prosper had "shot dead the three members of his family after a prolonged, violent struggle."
Prosper was seen by another Leabank neighbour at about 05:40. It was "pitch black" and Prosper was wearing a black top with its hood up, Cray says.
The prosecutor is now telling the court about how neighbours heard the attack in Leabank.
A woman who lived below the family heard banging that "sounded heavy and like people fighting" shortly after 05:00.
Cray says the neighbour decided to go upstairs and ask them to be quiet. When she arrived, she heard "banging and ruffling noises", as well as a boy groaning.
After knocking a third time, she heard a "big bang like a gunshot" and she fled to her bedroom.
Another neighbour said it sounded like someone's throat was being cut.
Cray says Prosper was "continuously" on his phone from 00:00 to 04:00 on the morning of the murders.
He searched online for "shotgun injuries to the neck" and other search terms, such as:
Cray says he also researched the murder of Sarah Everard.
Brian Farmer
Reporting from Luton Crown Court
Prosper is continuing to look down and around in the dock while the evidence continues.
His arms are folded and he is flanked by a security guard.
He shows no reaction as the court hears full details of his plans.
When interviewed by the police, the gun seller said he met Prosper in the car park of Leabanks.
He described the defendant as "polite and well-speaking" and "reasonable", and said he checked his shotgun certificate.
Prosper then paid him £650, plus £30 petrol money, Cray says. In return, the seller handed him the gun and 100 shotgun cartridges.
In the week that followed, Prosper searched online for St Joseph's and checked the advance weather forecast.
Prosper went on to tweak his forged shotgun certificate, using the signature of a sergeant in Bedfordshire Police's firearms unit.
He messaged another seller on 30 August, who was advertising a shotgun online for £450. Prosper offered to pay him £600 if cartridges were included, Cray says.
Prosper told him "he was a serious buyer and would be able to travel down" to where the seller lived to pay for it, cash in hand.
In a message to the seller, Prosper wrote: "Thank you for your corporation, [Sic] and please, since you’re the one making the journey, do be honest as I’d hate to make things more difficult for you."
The seller agreed to meet him on 12 September, with Prosper replying: "Sounds great! I’ve been investing so I wouldn’t mind throwing in some extra gas money as thanks."
The prosecutor says Prosper had an "obsession with mass killers".
One harrowing detail that has just emerged is that he emailed a woman whose child had been murdered, asking to see pictures of them.
Towards the end of August 2024, he emailed a man who was selling a double-barrelled shotgun online for £150.
Despite the asking price, Prosper offered the seller £500 - making him suspicious and ultimately avoiding the sale.
The judge has just been shown footage of Prosper appearing to practise shooting with a piece of wood.
On 12 June 2024, he downloaded a blank firearms certificate and went about forging his own one.
Cray says this was "crucial" in order to deceive someone into selling him a gun.
We're now hearing how Prosper booked a session at a gun club based in St Albans, Hertfordshire, on 15 September 2023.
He later admitted he had been thinking about mass killing for more than a year, but his plans stalled because he did not know how to get hold of a firearm.
In April 2024, he purchased a "distinctive" pair of black and yellow shoes for his attacks.
"This was, to his logic, a way that his acts might be remembered amongst the ranks of other notorious killers," Cray says.
It was in autumn 2023 that Prosper's internet history suggested he was planning a school shooting, Cray says.
He was found to have viewed images of notorious murders and rapists, as well of numerous school shooting scenes.
Prosper was showing a "deep alienation from normal life and interest in the darkest sides of humanity", Cray adds
Nicola Haseler
BBC News
At school, Prosper was a quiet, introverted boy who had a small group of friends and was interested in computers.
He didn’t engage with others, and didn’t want people invading his personal space.
Teachers thought he was on the autism spectrum; his mum and dad tried to get him help, but he refused to see the GP to get a referral.
The psychiatrist who assessed him said he had undiagnosed autism, but that’s not what drove him to do this. They said he had an extreme lack of empathy for others, rather than an impairment.
