The incident, details of which have been shared with the Union Home Ministry, occurred on April 16-17 intervening night when the passenger — Mohammed Qadir — wrote in the immigration form that the purpose of visit was “secret”, official sources said here on Friday.

The unusual mention raised the eyebrows of immigration officials who immediately detained the passenger and started questioning him, they said.

Qadir, who had arrived in India from Sydney via Singapore, later told the investigators he was in the city to collect a consignment from one “Robert Green”.