A teenager has been jailed for three years for making hoax bomb threats to hundreds of schools and a transatlantic flight.
George Duke-Cohan, 19, from Watford, admitted calls and emails that led to the evacuation of schools and an FBI investigation into threats against a United Airlines flight from London to San Francisco.
He had earlier made a bomb threat to his own school, West Herts College, where he was studying for an IT diploma.
The threat led to the college being evacuated, affecting 2,000 students. In February, he was excluded from college after admitting responsibility for the hoax.
Between 16 March and 19 March this year, more than 400 schools and colleges were forced to evacuate buildings after receiving emails threatening to detonate a bomb if a payment was not made to the sender.
The court heard that one of the emails, sent to a special needs school, read: "This is a message to everyone. We have sent in a student with a bomb… if you do not send the money we will detonate the device."
Thousands of pupils from 457 schools who received similar emails were affected causing anxiety and upset, Luton Crown Court was told.
Speaking to the perpetrator at the time, Sky News discovered that the emails were spoofed to look like they had been sent by Minecraft gaming network VeltPvP because the hoaxer was in a feud with the group.
Duke-Cohan was arrested within days, but while under investigation in April he sent a further mass email to hundreds of schools in the UK and the US claiming that pipe bombs had been planted on the premises.
The emails sent "resulted in widespread panic" the court heard.
They stated that a male pupil had plastic bottles with the explosive ANFO in his bag.
It said the senders "follow in the footsteps of our heroes who died at Columbine" referencing the massacre at Columbine High School in 1999.
"The point is that when you put the school on lockdown this student will set off the bomb, and will kill EVERY student in the room and maybe the rooms next to it," he said in an email, adding: "Natural selection is coming and we plan on being the ones to start it off."
While on pre-charge bail for the school hoaxes Duke-Cohan turned his attention to a transatlantic flight.
Making calls to both San Francisco Airport and its bureau police, he claimed there was a bomb on board flight UAL949, which was travelling from Heathrow to San Francisco with 295 passengers.
In one of the calls, Duke-Cohan pretended to be a father who had received a call from his daughter on the flight, saying the man behind her had a gun to her back.
In another call he claimed the flight had been hijacked by gunmen, one of who had a bomb.
The calls were taken seriously. When the plane arrived in San Francisco it was quarantined and all passengers told to remain on board while a full search was carried out.
The security operation took eight hours, causing significant economic loss to the airline, the court heard.
The court also heard how Duke-Cohan was a lonely, troubled child who had been bullied at school.
He began playing the game Minecraft and got validation from the people he met online.
It was as part of that online community that he was groomed by hackers, his barrister said. "He became involved in a toxic atmosphere," she told the court. "He started gaining the respect he lacked in his real, everyday life."
But the prosecution said that since he has been in custody "he has continued to display a fascination with bombs" and has been "bragging about his offences in prison".
In September, Duke-Cohan pleaded guilty to three counts of making hoax bomb threats following an investigation by the National Crime Agency.
NCA senior investigating officer Marc Horsfall said: "He carried out these threats hidden behind a computer screen for his own enjoyment, with no consideration for the effect he was having on others.
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"Despite being arrested and having conditions imposed restricting his use of technology, he persistently broke those conditions to continue his wave of violent threats.
"This investigation proves that operating online does not offer offenders anonymity. We will identify you and you will be brought before the courts."