Jakarta. North Jakarta’s Intercultural School (NJIS) received a bomb threat early Wednesday, but police confirmed no explosives or suspicious items were found after a full security sweep.

The alert arrived via email, claiming a bomb had been planted on campus and would detonate within 45 minutes unless a $30,000 ransom was paid in bitcoin. Authorities immediately dispatched officers to the school in Bukit Gading Raya, Kelapa Gading Barat, conducting a thorough search of the grounds, including the main building, lower floors, and outdoor areas.

“After receiving the report, we conducted a full check with our team. Nothing suspicious was found,” Kelapa Gading Police Chief Seto Handoko Putra told Antara news agency.

The incident follows similar threats against two other international schools in Greater Jakarta on Tuesday. Bomb-disposal teams inspected Nanyang School in Pagedangan, Tangerang Regency, and Mentari Intercultural School in Pondok Aren, South Tangerang, temporarily halting classes as a precaution. No explosives were discovered.

Authorities said the messages were sent via email and WhatsApp, with one traced to a Nigerian phone number demanding $30,000 in bitcoin. Police have described the threats as criminal extortion and terrorism attempts.

A joint investigation is underway, with Jakarta Police’s cybercrime unit tracing the origin of the messages and seeking to identify the perpetrators.