CID Superintendent of Police Ravindran said a team rushed to Tiruchirapalli on information that Shankar, arrested in a cheating case in that city, had admitted during questioning to having planted the object in the compartment.
The man was later brought here and remanded to five days custody.
A bomb disposal squad had retrieved the ball like object that day and after an examination, confirmed that there was no explosive barring some iron pieces with some adhesive like substance in a small container made of tin sheet. The object, was connected to a mobile phone. A hand written slogan was also found inside the suitcase which read 'Mayan Calendar.'
The materials have been sent for analysis to the Forensic Research Lab at Hyderabad and its report is awaited.