Senthil Kumaran, picked up from a house in Shornur in Palakkad district, told police that he had planted the "lunch box bomb" with the motive of causing trouble to a rival, one Thomas, police sources said.
Senthil had engraved the name of Thomas on the steel box which was found on the track near a rail bridge.It contained a metal plate on which the the name and number of his rival's motorcycle were also written, police said.
The lunch box containing explosive chemicals, timer, batteries and fuse wire was removed from the bridge across Muvvattupuzha river near Piravom Road station on Thursday.
The investigators obtained a lead in the case when they interrogated Thomas on finding his name on the steel box. He told police that it could be the handiwork of Senthil, with whom he had a fallen out some time back.
Thomas and Senthil, both bus drivers, were friends earlier but had a tiff sometime back over personal issues.
Senthil, missing for the last few days, was traced based on details obtained from Thomas when he was questioned, police said.
Police is on the lookout for another person, who is said to have helped Senthil in putting together the device, detection of which caused disruption of train traffic for over an hour on the busy rail route.
Kottayam (Ker): Police on Saturday arrested a 37-year-old man who was suspected to have planted a crude explosive device on the rail track near Piravom Road station between Kottayam and Kochi earlier this week.
First Published: Saturday, August 25, 2012, 13:08