A TEEN who murdered his mum and two siblings at his family home was also plotting a school shooting, police have revealed.
Nicholas Prosper, 18, today pleaded guilty to the murder of Juliana Prosper, 48, Kyle Prosper, 16, and Giselle Prosper, 13, whose were found dead together at home in Luton in September.
Prosper, 18, also pleaded guilty to a number of other offences during the Luton Crown Court hearing - including possession of a shotgun with intent to endanger life.
He also admitted possession of a bladed article, a kitchen knife, in a public place and purchasing or acquiring a shotgun without a certificate.
It can now be revealed that Prosper had been plotting a school shooting but was foiled by cops.
After murdering his family, the teen was stopped by officers near his home as he planned to carry out the massacre.
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Police also discovered a loaded shotgun discovered in bushes nearby alongside more than 30 cartridges.
Det Ch Insp Sam Khanna, from Bedfordshire Police, said "fortunately Prosper was apprehended before he could cause any further harm".
He continued: "This was a truly tragic and shocking case in which three innocent members of the same family have been brutally killed by their son and brother."
"No words can fully describe the tragedy their loved ones have experienced, and our thoughts continue to be with them at this difficult time.
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"We are pleased that Prosper has pleaded guilty and will not put his family through the pain of a trial, and that he will soon face a significant jail sentence."
The family shooting unfolded on September 13 at a flat on Wauluds Bank Drive.
Police swarmed the home at around 5.30am following "welfare concerns".
Horrified neighbours claimed they heard "loud bangs" that sounded like shots being fired.
Officers discovered Juliana and two of her four children dead inside the flat.
An inquest in October heard that all three of the victims died from gunshot wounds to the head.
Their devastated family said in a statement: "Julie was a strong, loving mother to her four beautiful children, who were her absolute world.
"In her spare time, she was a keen athlete and enjoyed raising money for charity - she was always putting others first.
"Kyle was a kind and funny young man who loved football and boxing.
"He was creative and thriving on TikTok, a big talent with massive potential.
"Kyle's friends were his everything.
"Giselle was a beautiful soul and caring young girl; she liked to laugh lots and loved her family and big brothers.
"She was so loveable with an infectious smile.
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"She was also an exceptional pupil at school and was loved dearly by her friends in Year 9."
Prosper was remanded into custody ahead of sentencing on March 5.