An autistic Irish teen, whose bomb hoaxes and murder threats in the U.S, caused undue mayhem and cost tens of thousands of dollars, has been released on two years probation.

Belfast Crown Court Judge Sandra Crawford told Ben Megarry, who is now 19, that while his crimes would typically require lengthy custodial sentences, there were several mitigating factors in his case, including his age (he was 15 at the time), and the link between his actions and his undiagnosed Asperger's syndrome.

The Irish Independent reports that the Co Antrim teen pleaded guilty to a total of 23 charges in which he made a number of hoax calls between March and September 2012 to "schools, businesses, public gathering places and airports within the continental United States.”

One of his targets was Columbine High School. On the 13th anniversary of the April 1999 shooting, Megarry phoned Columbine, telling the school principal he was not only "going to finish" what the two killers had started, but "he would not be so lucky ... and that he was going to die.”

Judge Crawford said that given the mitigating factors and a number of expert reports, she was willing to accept recommendations that there was a low likelihood of Megarry re-offending and believed he did not present a danger of harm to the public.

Megarry was ordered to complete 70 hours of community services.