Teenager gets 3 years in jail for sending thousands of bomb hoaxes to schools

A British teenager, 19-year-old George Duke-Cohan, has been sent to jail for three years for emailing thousands of bomb hoaxes to schools. He had also called San Francisco Airport pretending to be the father of a girl on a United Airlines flight who contacted him to say her plane was being hijacked.
According to NBC:

George Duke-Cohan, 19, touched off panic in March 2018 when he emailed thousands of schools, warning about an explosive. The National Crime Agency says more than 400 schools were evacuated.
He later caused a scare by telephoning San Francisco Airport and claiming his daughter had contacted him while on a United Airlines flight from Heathrow to say her plane had been hijacked.
Here are more details, including audio of his convincing call to the San Francisco Airport, as well as bodycam footage of his arrest, by BBC.