A teenager has been arrested over a bomb hoax that caused students at a prestigious Sydney high school to be evacuated as they were due to sit HSC exams.
A single threat was made to the academically selective North Sydney Boys High School last Thursday, after more than 30 schools were threatened across NSW on the previous two days.
Anonymous emails were sent to the schools on Tuesday and Wednesday but the threat to NSBHS was made with a phone call.
While it was suspected to be a copycat incident, staff and students at the Crows Nest school were forced to evacuate anyway, before HSC students were due to sit their modern history exam.
Modern history students later sat the exam at an alternative venue.
Cybercrime Squad detectives searched a south Sydney home on Wednesday morning, seizing a computer and mobile phone.
A teenage boy was arrested and taken to Kogarah Police Station, where police expect to charge him over the incident later on Wednesday.
Investigations into the origins of the other email threats, which are not believed to be linked to the North Sydney incident, are continuing.
Premier Gladys Berejiklian previously told reporters police had traced the source of the emails to eastern Europe.
The NSW Education Standards Authority said no student affected by the three-day saga would have to re-sit an exam and they would be given special consideration by markers.