Bengaluru, July 17 -- A bomb threat note found onboard an IndiGo flight moments before take-off sparked a major security alert at Kempegowda International Airport here, forcing the evacuation of passengers and a comprehensive anti-sabotage operation before the aircraft was cleared, police said on Friday.

The scare unfolded on Thursday evening aboard IndiGo flight 6E-6423, scheduled to depart for Ahmedabad at 8 pm. At around 7.35 pm, the cabin crew discovered a handwritten note in the aircraft lavatory warning of a bomb on board.

Security agencies immediately swung into action, deplaning all passengers and conducting an exhaustive search of the aircraft and baggage in accordance with aviation security protocols.

The operation found no exp...