Ludhiana: On Saturday, Sri Guru Harkrishan Adarsh Senior Secondary School in Dhandhra here received a bomb threat through email, which sent the school management into a tizzy. The Sadar police station began an investigation and the school was also shut down. While investigating the email, two mobile numbers were found, one of which was found to be operating in Bihar, while the other in Ludhiana. A minor boy from Ludhiana, who is a migrant, was detained and his interrogation is underway. The email threatening to blow up the private school was received by the principal. The police are investigating the email ID, which was sent from a mobile number registered in Bihar. Officials suspect that it could be a prank, but they are taking precautions. Meanwhile, ACP South Harjinder Singh confirmed to The Tribune that an anti-sabotage check was immediately conducted after the principal received the email and nothing was found.