The final act of Juliana Falcon’s life, in the minutes before she was shot dead by her son, potentially saved dozens of others.

Realising the unthinkable about her child, her intervention was crucial in preventing him from carrying out what could have been one of the worst mass killings ever to happen in the UK.

Triple killer who murdered family jailed for at least 49 years

It was late at night when the 48-year-old interrupted her teenage son, Nicholas Prosper, in his bedroom with a gun.

He was preparing to carry out a massacre at his old primary school the following day.

Police believe Juliana spotted the shotgun and confronted her son about what he was up to, and there was a struggle as he began attacking his mother.

Her intervention changed everything.

Prosper, 18, shot his mother dead with the firearm he had bought illegally less than 24 hours earlier.

Over the next few hours in the family’s eighth-floor flat in Luton, he also shot dead his 13-year-old sister, Giselle, and shot and repeatedly stabbed his 16-year-old brother, Kyle.

The noise of the killings alerted neighbours and meant police would be on their way, so Prosper’s plan had to be brought forward.

“My f****** mum messed it up,” he wrote down while in custody. “My mother is a f****** stupid cow.”

A plan for ‘notoriety’

Prosper left the flat at 5.30am on 13 September last year, hours before the school would open.

He had meticulously researched school massacres, was fascinated by violence and led a dysfunctional life online. He craved notoriety.

He took with him more than 30 shotgun cartridges which, he had calculated, would enable him to kill more children than any other school attack.

When he was arrested, he was on his way to his old primary school to target the youngest children there, aged just four and five.

In a note he later wrote in prison, he confessed he “wanted to cause the biggest [school] massacre in the 21st century and be more famous than Sandy Hook”.

A total of 26 children were killed at Sandy Hook Elementary School in Connecticut, USA in 2012. The killer there had shot dead his own mother at home before going to the school.

Prosper’s mother’s actions in Luton, disturbing his plan early, denied him that appalling place in history.

Senior investigating officer Detective Chief Inspector Sam Khanna, of Bedfordshire Police, told Sky News that Prosper’s ambition “was most definitely notoriety… to be known as being responsible for the biggest school shooting on record.”

He had researched in detail every shooting school shooting across the world “within the last 15, 20 years,” he said.

“He’d done his sums, and he wanted to be responsible for the most amount [of deaths]. Killing his family was the first part of it. But then going to a school and killing numerous children, teachers, then finally himself.”

Concerns raised

Prosper was raised in Luton and had attended St Joseph’s Catholic Primary School, where he planned to carry out an attack three-quarters of a mile from his home.

Growing up, teachers thought he was a quiet, introverted boy, with a small group of friends who were interested in computers.

When he went to sixth form aged 16, staff noticed he had become more withdrawn.

The school raised concerns that he could be on the autism spectrum, but he refused to see a GP or accept any help.

DCI Khanna said “very little” was known of Prosper, and “there was certainly no Prevent referral”.

Prevent is the UK’s counter-terrorism programme designed to identify and stop young people being radicalised.

Both of Prosper’s parents “had expressed concerns to the school”, the detective said.

The school had shared those concerns, he said, “but because of his unwillingness to engage with mental health professionals, it didn’t go any further”.

A consultant forensic psychiatrist concluded the teenager shows “all the symptoms of Autism Spectrum Disorder (ASD)” but that it was undiagnosed at the time of the killings. He said Prosper has “an extreme lack of empathy with others and an extreme lack of remorse”.

Read more:
What is Prevent?

How did Prosper get a gun?

So how was an 18-year-old able to source a shotgun? The answer is by deception.

Prosper convinced a legitimate seller, who had only previously sold to registered firearms dealers, to deliver the weapon to him.

The teenager produced a convincing but fake shotgun certificate and paid the seller £650 in cash and an extra £30 petrol money to bring the gun and 100 shotgun cartridges to Luton the day before the killings.

Bedfordshire Police investigated and concluded the seller would not face criminal charges. He had been duped by Prosper.

DCI Khanna said Prosper “went to great lengths, looking at templates, looking at prototypes, getting police force logos, signatures, and having copies of genuine certificates, so he could produce what he thought would be good enough to enable him to obtain that shotgun – even down to the printing of the paper with watermarks”.

Prosper spent a lot of time online alone in his bedroom posting troubling comments supporting sexual relationships between adults and children and expressing other extreme views.

He had also become obsessed with the Walking Dead video game, and particularly a character called Clementine who is a vulnerable young girl.

Detectives can’t say if there is a direct link between his “avid use” of the game and the school shooting plan, but it is one aspect of a complex and unhealthy life he led online.

DCI Khanna said Prosper “certainly believed that he had some form of relationship with Clementine, albeit she’s a video game character”.

Police also found indecent images of children on Prosper’s devices.

The investigator said his online research of school massacres was persistent and extremely detailed.

“There’s a lot of talk about the dark web, but this was on the surface web and sites where… you can read manifestos of people that have done horrific acts. They shouldn’t be available to be seen.”

After his arrest, Prosper told a nurse at Bedford prison about his school massacre intentions. He had also written two detailed plans of what he intended to do at the primary school he used to attend.

“We didn’t find any evidence that he had harboured any grudges towards that particular school… it was purely around his knowledge of it,” DCI Khanna said.

After killing his family, he left home “with the right amount of cartridges to complete his plan, right down to the final detail”, he added.

“Once in prison, he has openly talked about the fact that that was his plan – to go to the school and kill children and teachers before finally killing himself.”

Prosper had chosen black and yellow clothes for the attack and as he made his way towards the school in Luton he was spotted by police officers on patrol.

They thought he was acting strangely and knew three members of the same family had been shot dead nearby.

“It’s not murder,” he repeatedly told the officers as they handcuffed him by the roadside.

Months later, he pleaded guilty shortly before he was due to stand trial.

Remembering the victims

The dilemma of whether to make his school shooting plan public has been difficult for police and prosecutors.

It is clearly deeply upsetting for the school community and they are mindful that Prosper craved attention and publicity, but it is also about challenging this kind of extreme behaviour online.

DCI Khanna’s investigation team has examined this “deeply troubling” case with the victims at the forefront of their minds.

“The family has really told us what wonderful people they were,” he said.

Juliana, he said, was “a doting mum who did a lot of work for charity and [was] a very keen runner”.

He described Giselle as “so popular amongst friends, a bright girl with an infectious smile”, while Kyle was a “funny young man, really into his sports and again very popular at school with his friends”.

Now, DCI Khanna said, the focus should be on the victims – “and how much they’ll be missed”.