A TEEN who murdered his mum and two siblings boasted about mutilating his 13-year-old sister just hours before.
Nicholas Prosper shot dead Juliana Falcon, 48, Kyle Prosper, 16, and 13-year-old Giselle Prosper at their home in Luton in September.
Nicholas Prosper will be sentenced on March 5[/caption]
The 19-year-old had also intended to carry out an attack at the school and a loaded shotgun with more than 30 cartridges was found in a bush after his arrest, police said.
In now deleted videos, Prosper had spewed his vile views which included his sick obsession with children.
One clip recorded hours before he massacre saw him threaten violent revenge against his 13-year-old sister Giselle over her actions on a computer game.
Prosper said: “On June 30, my sister decided to make the incorrect choices on episode one of season one of The Walking Dead games, and for that her face will be mutilated further than necessary.”
Prosper said he was “chosen” to protect a fictional character called Clementine in the zombie video game, in a sign he struggled to differentiate between the real world and make-believe.
The 19-year-old pleaded guilty to three counts of murder at Luton Crown Court on Monday.
It was also 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.
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.
“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.
Prosper is on remand at HMP Peterborough, but he appeared for the hearing yesterday which lasted less than 10 minutes.
He wore a black t-shirt, dark trousers and black rimmed glasses as he entered his pleas.
The 19-year-old sat with his arms folded when he entered the dock.
As well as admitting the three murders, he pleaded guilty to purchasing or acquiring a shotgun without a certificate, possessing a firearm with intent to endanger life and possessing an article with a blade or point.
He is due to be sentenced on March 5.
