Preliminary investigations by the Bureau of Civil Aviation Security (BCAS) and the Central Industrial Security Force (CISF) into the firecracker-on-plane incident indicate that the firecracker made its way to the Kingfisher flight in Thiruvananthapuram, and not at the Bengaluru International Airport.

Sources in the CISF, which provides airside security at airports, told The Hindu on Thursday that since the available leads indicated that the firecracker found its way to the aircraft at Thiruvananthapuram, the investigation was handed over to the police there.

It was for the police to probe how the packet containing the firecracker reached the aircraft, and who were involved in it, the sources said.

A firecracker wrapped in the Thiruvananthapuram edition of a Malayalam newspaper was found in the flight, which originated from the Bengaluru International Airport, after it reached Thiruvananthapuram on Sunday morning.

A team of officials of the BCAS from New Delhi arrived at the Bengaluru International Airport at Devanahalli, near here, on Monday and investigated the incident, which raised concerns about aviation safety and security.

Claiming that there was no security lapse at the Bengaluru airport, the sources said there was no truth in the reports that the Kingfisher aircraft remained unguarded for more than 45 minutes prior to its departure.