An Israel-American teen has been charged with 31 counts after allegedly threatening Jewish centres, schools and commercial flights across the US, New Zealand, Australia, and Canada.
Michael Ron David Kadar, 18, was arrested in Israel in March. A dual US citizen, he is being charged in Georgia and Florida, according to NBC News.
Israeli prosecutors say Kadar made more than 2000 threatening calls to schools, airports, police stations and hospitals, the BBC reported.
In one February 2017 call, Kadar promised that 'in a short time, a large number of "Jew children" were going to have their heads blown off from the shrapnel,' an FBI report alleged.
Kadar is Jewish, an official told ABC 7. He hid his voice with voice-modulating software, the Daily Mail reported.
The calls date back as far as August 2015, and frequently saw Kadar threatening 'bombs' and 'bloodbaths', the FBI said.
He disguised his identity by using text-to-voice services and voice modulation software.
And he equipped his home with an antenna that allowed him to use multiple wi-fi connections in his neighbourhood to further hide his identity.
But the FBI were able to track the calls after serving 100 subopenas and search warrants to various internet providers. One of his threats to a New Zealand Jewish institution was reportedly traced to an IP address in Israel.
They then tracked the time of day and phrases to pinpoint the suspect.
The Jewish Museum in London was evacuated after a bomb threat attributed to him, the BBC reported. Swiss and French warplanes were scrambled to escort an El Al flight to Israel, after Kadar falsely claimed a bomb was on board. A hoax threat reportedly forced the diversion of a passenger plane.
According to the Florida indictment, which covers calls made between January 4 and March 3, when the voice modulation was stripped out, the recordings retained a speech impediment similar to Kadar's own.
And Israeli police said that his home contained recordings of the calls, organised by date, on a USB drive.
He has been charged with 28 counts of making threatening calls and conveying false information to police in that state.
The Georgia case involves Kadar allegedly reporting a fabricated home invasion and shooting in order to get a location 'swatted' - that is, raided by police as a 'prank'.
There, he has been charged with three counts of making threatening calls, conveying false information and cyberstalking.
Both Kadar's mother and lawyer claim that his actions were likely influenced by his autism and an inoperable brain tumour.
"The best surgeons in the world refused to operate on him due to immediate danger for his life," his lawyer, Shira Nir, told NBC News.
At the time of Kadar's arrest, his lawyer had claimed that his condition had stopped him going to school, and had got him out of compulsory enlistment in the Israeli Army.
The Jewish Community Centre Association said in a statement that it was "troubled to learn that the individual ... is reportedly Jewish".