Intensifying its probe in the cash-for-vote scam, Telangana's Anti-Corruption Bureau (ACB) on Wednesday grilled Telugu Desam Party (TDP) leader and fielded MLC candidate V. Narender Reddy for four hours.The ACB late on Tuesday had served notice to TDP legislator Sandra Venkata Veeraiah and Narender Reddy, who is the TDP-BJP candidate in Telangana legislative council elections. They were asked to appear before the ACB for questioning.Sandra Venkata Veeraiah is yet to appear before the investigating agency. As Veeraiah was not available at his residence, the officials pasted the notice on the residence door. Though the officials asked Narender Reddy to accompany them, he sought time till Wednesday.Narender Reddy on Wednesday morning reached ACB headquarters in Banjara Hills. A team of officials questioned him as he is alleged to be the ultimate beneficiary in the case, sources said. (Vem Narender Reddy)The questioning began amid reports that ACB is planning to issue notices to TDP president and Andhra Pradesh Chief Minister N. Chandrababu Naidu and two party MPs.For a second consecutive day, Hyderabad witnessed hectic activity relating to the case. Telangana Director General of Police (DGP) Anurag Sharma, ACB chief A.K. Khan and Hyderabad Police Commissioner Mahender Reddy on Wednesday met Chief Minister K. Chandrasekhar Rao.The DGP had also called on the chief minister on Tuesday while Khan met him twice.TDP MLA A. Revanth Reddy was arrested by the ACB on May 31 while he was offering Rs.50 lakh to nominated MLA Elvis Stephenson reportedly to induce him to vote for Narender Reddy.In a trap laid on Stephenson's complaint, the ACB also arrested Revanth Reddy's aides Sebastian Harry and Uday Simha.ACB has already questioned the three accused with regard to the source of the Rs.50 lakh and also from where they planned to arrange the remaining Rs.4.5 crore as the deal was reportedly struck for Rs.5 crore.ACB called Narender Reddy and Veeraiah after analyzing the call data of Revanth and two other accused.An audio tape of Chandrababu Naidu's alleged telephonic conversation with Stephenson surfaced on June 7. The Telangana Rashtra Samithi (TRS) government has alleged that Naidu is the mastermind of the scam.Meanwhile, the ACB is set to record Stephenson's statement on Wednesday. The nominated MLA, representing the Anglo-Indian community, will give his statement before a magistrate.In another development, Hyderabad High Court adjourned till June 24 the hearing on a bail petition of Revanth Reddy.With IANSCorrection: An earlier copy suggested that Narender Reddy was arrested when in fact he was only questioned by the ACB. It was learnt later that the TDP leader returned to his quarters. The News Minute regrets the error.