The sliding doors moment that stopped Sandy Hook-obsessed killers school massacre

Teenage killer Nicholas Prosper shot dead three members of his family and was planning to attack his former primary school. What drove his obsession with mass killings and how was he stopped from committing further atrocities?

Prosper, 19, is beginning a life sentence for murdering his mother Juliana Falcon, 48; his brother Kyle, 16, and sister Giselle, 13, at their flat on Lutons Marsh Farm estate.

At Luton Crown Court, he was told he must serve at least 49 years in jail.

However, the death toll could have been even higher were it not for the vigilance of the police officers who spotted and arrested Prosper before he could enact plans to murder primary school pupils and staff.

A senior detective described that as a "sliding doors moment", while one of the arresting officers said the knowledge he had prevented further killings was "very overwhelming".

Sentencing, Mrs Justice Cheema-Grubb told Prosper: "You intended to unleash disaster on the community of Luton. Your plans were intelligent, calculating and selfish. Your ambition was notoriety."

Warning: This story contains distressing details

Prosper killed his victims in the early hours of Friday, 13 September last year.

An inquest heard each had gunshot wounds to the head. Kyle had more than 100 knife wounds. Giselle had been shot in the face.

It was the first phase of an intended assault that had been a year in the planning.

Prosper planned to attack St Josephs Catholic Primary School in Gardenia Avenue, Luton, killing 30 young children and himself.

The date was no accident. He had chosen Friday the 13th "so it had a good name on it", the court heard, and had also designed a distinctive black and yellow outfit to wear.

"He wanted to be the most notorious and infamous person thats ever committed a school shooting," said Det Ch Insp Sam Khanna, of Bedfordshire Police.

"He knew numbers; he knew facts and figures, and he wanted to be responsible for the most number of casualties ever killed within a school."

In August 2023, Prosper made a booking at a shooting range, but did not attend.

However, his online history gives an fuller insight into what drove him.

"Theres a general theme of extreme violence; content which you cant believe is readily available on the internet," said Det Ch Insp Khanna.

"Theres pretty much not a mass shooting event that he hadnt researched in detail.

"He had a fascination with the people that perpetrate such offences and had gone to great detail researching them, almost putting together fact-files of them."

One of those spree shootings was at Sandy Hook, the Connecticut elementary school where 26 people were killed in 2012.

Prosper was determined to murder more.

The BBC has previously reported he was banned from a website featuring videos of peoples final moments, after making pro-paedophile comments.

By April 2024, he became a member of an online gun sales website, and three months later began researching how to fake a firearms certificate.

He then turned to researching his former primary school.

Police found no evidence he had a bad time there or bore any grudge, rather that his first-hand knowledge "would make his plan that much easier", said Det Ch Insp Khanna.

In August, Prosper tried and failed in his first attempt to buy a gun.

However, later that month he contacted another seller on a legal gun sales site, paying £650 plus £30 petrol money to the man for a shotgun and 100 cartridges.

"He basically created a legend of himself to make any would-be seller feel comfortable," said Det Ch Insp Khanna.

"He went to the lengths of talking about working for a charity as a volunteer to gain the confidence of the seller."

He researched the logos, signatures and even the type of paper licences were printed on to fool the seller, who police found had committed no offence.

"It is a fake, but possibly only an expert would know that," said Det Ch Insp Khanna.

The seller notified Bedfordshire Police of the sale on 12 September.

Because this was done out-of-hours on the day before the killings, there was no opportunity for anyone to realise the gun had been sold to someone who was not a legitimate licence-holder, said Det Ch Insp Khanna.

"This cant be allowed to happen again... the Bedfordshire deputy chief constable is engaging with national parties to try and look at this and see what learning can come from it," he added.

The court heard Prosper planned to shoot and rape Giselle, but his mother "messed it up" by waking up.

Kyle hid in the kitchen and "began pleading for his life" during the attacks.

Marium Abbas lived in a flat above theirs. In the early hours of 13 September, she awoke to banging and a "strange voice which Ive never heard, never experienced, in my life".

She went outside her door and saw a neighbour. They discussed calling police, but concluded they did not know what they would tell them.

Later, officers surrounded the building and Ms Abbas learned of the horror that had unfolded beneath her.

Despite since being reassured by friends, she said she still felt "guilty" and struggled to be alone.

"I feel like maybe if I knew what was happening; if I went downstairs; maybe he would have shot me but the children would have been saved," she said.

After the killings Prosper went on the run. His arrest, soon afterwards, was a "sliding doors moment", said Det Ch Insp Khanna.

Two officers returning from the scene to the police station spotted a man whose "whole behaviour was off".

"Nothing was really said in the car," recalled one. "I think we kind of had the same instinct... This seems related.

"As we get closer, we start to see what appears to be blood over his face. At that moment, we believe he was our suspect.

"We got him into handcuffs. He just kept on saying Its not murder, its not murder."

Officers found a shotgun and 33 cartridges in a nearby bush.

The officer said when he learned the extent of Prospers plans, it was "very overwhelming knowing that it was me and my crewmate that managed to prevent this from happening".

Prosper made disclosures to a prison nurse four days after the killings, and also produced two written plans in jail.

"Very unusually for most of our cases, he has been talking," said Det Ch Insp Khanna.

"In terms of why we think hes done this, its purely around notoriety and wanting to be known for a significant horrific offence and event.

"Normally we get people in his position that dont talk and wait for the legal process to go through, but thats the opposite we found with the offender."

There is no evidence to suggest Prosper was seeking to advance a political or ideological cause.

He was not charged with terrorism offences, and nor was he known to the government anti-terrorism programme Prevent.

His parents were separated, but both of them and his school had concerns about Prosper and he was referred to a GP.

But he refused to engage and that went no further.

NHS Bedfordshire, Luton and Milton Keynes Integrated Care Board NHS has declined to comment, while East London NHS Foundation Trust, which provides mental health services in the area, said Prosper was not under its care.

While in prison, a forensic psychiatrist assessed Prosper as having autistic spectrum disorder traits, but he has not been officially diagnosed.

However, it was determined that it was not these traits that drove his actions; rather, his desire to become infamous and a lack of empathy for others.

Prosper also had a number of indecent images of children on his phone, but because of the severity of the other charges he faced, the Crown Prosecution Service decided against a specific charge on these.

At Prospers first court appearance, his father Ray Prosper shouted: "I still love you, son. Its not your fault, OK?" and then wept.

At the sentencing hearing, a statement he wrote was read out on his behalf.

"When I heard the horrendous news that day, part of my soul died too. This is a lose-lose situation for us all and we have lost four family members," he wrote.

Det Ch Insp Khanna said: "Were used to going and seeing families and loved ones at the most challenging of times and telling them that unfortunately theyve lost a member of their family.

"For the offenders father, hes lost two of his children. Hes lost his ex-wife, who he still had a good relationship with, and this has been perpetrated by his own son."

He said police were supporting family members, but added: "I think it would take a long time before anyone can come to terms with whats happened."

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