A man who targeted dozens of schools, the Super Bowl and the Houses of Parliament with hoax calls has been jailed for more than four years.
Andreas Dowling and others members of a small online group used software to disguise their voices while calling in bomb threats.
Over the course of two months in 2016 he caused substantial disruption to the educations of thousands of pupils and sparked major police responses by phoning in bogus threats to 75 schools across England.
He also targeted the New England Patriots vs Seattle Seahawks Super Bowl XLIX game on February 1, 2015.
In November the 24-year-old pleaded guilty at Bristol Crown Court to 31 charges relating to 107 offences.
Investigators started looking into Dowling after a school in Cornwall and several in Bristol were targeted by bomb hoaxes.
They discovered that in January and February 2016 75 schools across London, the West Midlands, Devon, Cornwall, Avon and Somerset, and West Yorkshire had all fallen victim to the threats.
After becoming aware of similar hoaxes taking place in the US around the same time, investigators made contact with the FBI and together they identified Dowling as a suspect.
When officers searched his house in Torpoint, Cornwall they found an eBook which included chapters about how to make bomb threats to high schools and a step-by-step guide on sending armed response officers to people's homes.
They also uncovered a file titled 'bomb threats by email'.
American and Canadian schools also fell victim to his calls, as did the Palace of Westminster, police stations and Super Bowl XLIX - a sporting event watched by 120.8 million people.
He also made bomb threats against Jewish schools in crimes that were treated as being "racially aggravated".
Dowling pleaded guilty to a single charge of "encouraging or assisting the commission of an offence believing it would be committed" under the Protection of Children Act 1978.
This related to Dowling threatening to "ruin the life" of a 17-year-old girl in the US unless she sent him nude photographs of herself.
At the beginning of November the defendant, who is deaf, was assisted in entering his pleas from the dock by a lip speaker.
