A Malaysia-bound air passenger from here was detained by the Customs authorities at the airport here on Saturday after they found some chemical substances weighing four kilograms in his alleged possession.

The sample of the seized item will be sent for testing to ascertain whether it is a narcotic substance. Sources said the passenger Basith Ali, of Tiruchendur in Tuticorin district, came to the airport to board a flight to Kualalumpur when the Customs authorities on information checked the passenger and noticed chemical substances in his possession. Further investigations are on.