The Delhi Police had questioned about a dozen persons in connection with the case after bringing Dinakaran and Mallikarjuna in Chennai on April 27.
Those suspected to have been linked with the money trail in the bribery case and others who had knowledge about the transaction were questioned, police sources said.
Mr Dinakaran was arrested on April 25 in Delhi following four days of questioning for allegedly attempting to bribe an unidentified election body official to get the undivided AIADMK's 'two leaves' election symbol for his faction.
Police had earlier arrested Sukesh Chandrasekar, who had allegedly struck a deal for Rs 50 crore to help the AIADMK (Amma) faction acquire the party symbol, and seized Rs 1.30 crore from him.
A Delhi court had granted five days police custody of Mr Dinakaran following which he was brought here.
Yesterday, the police team visited various areas, including Adambakkam and Kolapakkam in Chennai, to question some persons whose identity has not been disclosed.
Police sources said the probe will continue, but declined to comment if any documents had been seized.