Mumbai | A threatening note was found in the lavatory of a Chennai-Mumbai IndiGo flight on Tuesday morning, police said here.

Nothing suspicious was found on the aircraft and a First Information Report (FIR) was registered against unidentified persons for mischief, said an airport police station official.

The note, scribbled on tissue paper, was found minutes before the plane landed.

"If you come to Mumbai, everyone will die," it read.

The cabin crew immediately alerted the captain who informed the Air Traffic Control about the incident, the official said.

The entire plane and passengers were searched but nothing suspicious was found, he said.

An FIR was registered against unknown persons under relevant sections of the Indian Penal Code including section 505 (statement conducing to public mischief) and further investigation was underway, the official added.

''IndiGo flight 6E 5188 operating from Chennai to Mumbai had received a bomb threat post landing in Mumbai. All necessary protocols were followed and the aircraft was taken to a remote bay as per guidelines by airport security agencies,'' the airline said in a statement.