Delhi Police on Monday booked AIADMK Deputy General Secretary and Sasikala's nephew T.T.V. Dinakaran on charges of bribery, an officer said.
Dinakaran has been accused of attempting to bribe Election Commission officials to get the party's 'two leaves' symbol.
Police said his close aide Sukesh Chandrasekar was arrested on Sunday night from a south Delhi hotel with Rs 1.3 crore which he was to give the poll officials as a bribe in exchange for the symbol that was suspended a couple of weeks ago.
"Dinakaran has been booked for criminal conspiracy, personating a public servant and corruption after Chandrasekar disclosed his name during a late night police raid at the hotel where he was staying," the senior police officer said.
The police had raided the hotel following a tip-off, the officer added.
The AIADMK has been cleaved into two camps since December 2016, when its leader and late Tamil Nadu Chief Minister J. Jayalalithaa died.
Her closest aide, V.K. Sasikala, was named the new party chief but was jailed within weeks after the Supreme Court found her guilty of corruption.