A group of hackers claiming to be from Switzerland have said they are responsible for the bomb hoax sent to more than 400 schools across the UK.
A group called Apophis Squad tweeted a cryptic message about Monday's bizarre attack, suggesting they ran it through a Minecraft gaming server because it was not of "good standing".
The tweet, which had a Matrix-style graphic attached, read: "Addressing the email attack we did and our motives. We ask that you think about why we would do this.
"If Velt was a good standing network this would NEVER of happened. They lie to you and they lie to the press."
Addressing the email attack we did and our motives. We ask that you think about why we would do this. If Velt was a good standing network this would NEVER of happened. They lie to you and they lie to the press. @VeltPvP pic.twitter.com/T0SHEpH9MC— APOPHIS SQUAD (@ApophisSquad) March 21, 2018
VeltPvP is the US-based gaming network from which the emails initially appeared to have been sent.
The company's CEO, 17-year-old Carson Kallen, told the BBC the messages were not from them but seemed to be so because the account used to send them had been "spoofed".
A message posted to VeltPvP's Twitter said: "We have nothing to do with the bomb threats that were sent out to the 400+ UK schools.
"We're extremely sorry for anyone who had to deal with this, but just know it's fake."
Mr Kallen told the BBC he thought the culprit was a disgruntled Minecraft gamer who wanted to damage the network's reputation.
Please ignore any emails that do not originate from veltpvps verified SMTP services.— VeltPvP (@VeltPvP) March 19, 2018
The user was spoofing his email address to make it look like it was coming from our email address.
Here is an example on how email spoofing works:https://t.co/o7tjAJPZYx
VeltPvP.com is a server that allows gamers to compete with each other on Minecraft, a popular world-building game.
More than 400 schools and colleges across the UK received the email threat on Monday, according to police.
“The emails inform the school that a bomb has been placed on the grounds and will be detonated if they don’t hand over cash,” Northumbria Police said in a tweet.
Horrified parents told how they dashed to pick up their kids after schools were evacuated in the wake of the threat.
The hoax email is believed to read: "This is a message to everyone. We have sent in a student with a bomb. The bomb is set to go off in 3 hours time. If you do sent $5,000 USD to payments@
"If you do not send the money! We will blow up the device. Our site has all the information needed
"If you try to call the cops we WILL blowup the device on the SPOT! ANY attempt at defusing it your self will cause it to explode."
It was then followed by writing in Arabic script.
Parents described the hoax as "horrific" and "disgusting".
One woman wrote on Twitter: "My daughters school has been evacuated because of a bomb threat and I’m still miles away in an Uber racing to get her home safely.
"Please don’t **** with other people’s kids. There’s so much wrong with this world," she added.