LUCKNOW, Oct. 1 -- Lucknow Police on Monday registered an FIR after authorities at Chaudhary Charan Singh International Airport here received a bomb threat email warning of explosions at the airport, other Airports Authority of India facilities, and several city schools. Vipul Kumar, terminal manager at Lucknow airport, lodged the complaint stating the suspicious email was received on Sunday on the airport's official ID. The email reportedly threatened to blow up the airport and other locations. Following the complaint, Sarojininagar police filed a case under Section 66 of the IT Act and Section 351(4) of the Bharatiya Nyaya Sanhita (BNS). "Investigators are working with cyber experts to trace the source of the email," Sarojininagar station house officer Rajdeo Ram Prajapati said. He added that security has been tightened at the airport and other sensitive sites while the preliminary investigation is ongoing....