Bangalore/Thiruvananthapuram, March 22 (IANS) A day after explosives were found in the cargo section of a Kingfisher flight, police in Bangalore Monday admitted security lapse but said it might have been placed in Thiruvananthapuram.

'It might have been placed in Thiruvananthapuram only, though there is some security lapse at Bangalore airport also because the same aircraft that landed here late Saturday and took off Sunday morning,' Basavaraj Malagatti, deputy commissioner of police of North-East Division, told IANS.

Kingfisher Airlines flight IT 4731 took off from Bangalore International Airport with 27 passengers and four crew members onboard and landed at Thiruvanathapuram at 8.25 a.m.

Soon after landing, a Central Industrial Security Force (CISF) official reportedly discovered crude explosives, a cocktail of sulphur, potassium chlorate and aluminium powder, in the cargo hold.

The discovery triggered panic alarms in Bangalore and Thiruvananthapuram, leading to a high-level investigation on how it got past the many layers of security.

The plane later was allowed to fly back to Bangalore in the afternoon after thorough security check.

'We have questioned people on duty at cargo section and at various security check-points at Bangalore airport. We believe the device might have been placed in the aircraft at Thiruvanathapuram Saturday (before it took off for Bangalore).

The reasons for the Bangalore police to come to this preliminary conclusion is that the device was not in any baggage, was wrapped in a Secondary School Leaving Certificate (Class 10) question paper of Kerala State Education Board and a Malayalam newspaper.

Malagatti said a Kerala police team had Sunday interrogated over 20 people on duty at various divisions at the Bangalore airport and the airline officials Sunday.

'The team has gone back to Kerala,' he said.

Malagatti said though the Bangalore police believe the device might have been loaded at Thiruvananthapuram, investigations at the Bangalore end are still continuing.

Meanwhile, Kerala Director General of Police Jacob Punnoose said the probe is on but there has been no breakthrough yet.

'There were 27 passengers on board. We are yet to identify all the passengers because these days booking is done through the internet and hence the delay in identifying them. The copies of the video footage are also being collated from Bangalore and from here,' said Punnoose.

Punnose confirmed that a Kerala police team had gone to Bangalore and said they have now come back.

'Our officials are leaving no stone unturned and all possible leads are being examined,' he said.