Mr Dinakaran reached the Crime Branch Inter State Cell office in Chanakyapuri around 3:30 pm, even as the police started by interrogating his personal assistant Janardhan.
They also quizzed his long-time friend Mr Mallikarjuna, who has been accompanying him everywhere ever since Mr Chandrasekar was arrested, police said.
It was only around 6 pm that Mr Dinakaran's questioning began and came to an end around an hour post-midnight, they said.
On sustained quizzing, Mr Dinakaran said he had met Mr Chandrasekar, who had posed as a high court judge and sought to help him in the matter, police sources said.
However, he denied paying money to the middleman, the sources said, adding the Crime Branch officers also confronted Mr Dinakaran and Mr Chandrasekar. He has been called for questioning again today at 5 pm.
B Kumar, Jayalalithaa's lawyer and her key aide, also came to the Crime Branch office in Chanakyapuri late last evening. He is likely to be questioned tomorrow in connection with the case, they said.
On Sunday, he was grilled by the police for 11 hours. The controversial leader was earlier summoned by Delhi Police at his Chennai residence in the case.
Having been appointed as deputy general secretary by jailed AIADMK chief V K Sasikala, Mr Dinakaran has been isolated in his party amid moves to merge rival factions led by Tamil Nadu Chief Minister E K Palaniswami and his predecessor O Panneerselvam.
A powerful section of the ruling AIADMK (Amma) recently revolted against Sasikala-Dinakaran leadership. The development came after Mr Panneerselvam, who is leading the rival faction, demanded ouster of Ms Sasikala and Mr Dinakaran as a condition for the merger.
Mr Dinakaran later announced he would stay away from party affairs and that he could be removed only by Ms Sasikala.
Ms Sasikala is at present serving a four-year jail term in Bengaluru in a disproportionate assets case.