Police identified the man as Vijayan, a native of Kozhikode, Kerala. 

Police said he was in Chennai looking for a job and had travelled from Coimbatore to Chennai by train on Thursday afternoon. 

On scanning his bag at the Metro station, security personnel found a gun. Further search resulted in seizure of as many as 10 debit / credit cards. 

It is not clear a man claiming to be looking for a job was in possession of a gun and so many debit and credit cards.