According to police, there was no evidence to link the incident to any terror group and that the incident was an act of personal vendetta involving a single person, Rajashekharan, employed with a firm which airport authorities had hired. Police sources said Rajashekharan, a cleaning supervisor with Universal Aviation Private Ltd., planted the crude bomb before the flight’s takeoff to Bangalore and reported it to security staff claiming he found the bomb while cleaning the aircraft.

Rajasheskharan, who had previously worked as a sergeant with a major airport security firm, Central Industry Security Forces (CISF), acted alone out of a personal vendetta he held against former colleagues.

He had hoped to pin the blame of the major security lapse on his former colleagues.

The crude bomb, the size of a cricket ball, was wrapped in a newspaper and found in the cargo hold of the Kingfisher plane after it landed in Thiruvananthapuram from Bangalore on March 21.

The flight had 27 passengers and four crewmembers. The Bureau of Civil Aviation Security (BCAS), the regulatory authority for civil aviation security in India, is probing the security lapse.