Police said one Zakir Hussain was arrested from his residence at nearby Tirunagar. He was later questioned and produced before the Tirumangalam Judicial Magistrate, who remanded him in custody till April 10.
They said cases have been registered against 10 persons so far, of whom seven have been nabbed.
Three more accused including 'Police' Fakruddin, the kingpin, are still absconding and a hunt is on to arrest them. The special teams are camping in various places in Chennai to nab them.
Sleuths had detected and defused the bomb before Advani's cavalcade crossed the bridge.