NEW DELHI: The Anti-Corruption Branch on Wednesday questioned Delhi Chief Minister Arvind Kejriwal's private secretary Bibhav Kumar in connection with its probe in the alleged Rs 400 crore tanker scam.

Sacked Delhi miniter Kapil Mishra had accused Bibhav and Kejriwal's political advisor Ashish Talwar of influencing the probe in to the tanker scam that dates back to Sheila Dikshit's tenure as chief minister.

Kumar had reportedly been asked to bring some files.

Mishra, during his protest strike against Delhi CM, had alleged that the investigation into the scam was delayed by Kejriwal and his "two men".

The sacked minister also claimed that Kejriwal's aide had asked him to delay sending of a few reports to the then Lieutenant Governor Najeeb Jung in connection with the alleged scam, PTI quoted a source as saying.

Mishra had also accused the state government tried of shielding Sheila Dikshit and declared himself as a witness into the scam.

During a presser AAP had refuted Mishra's charges saying it was Mishra who had repeatedly said that Kejriwal "had nothing to do with the scam" and the ACB was under pressure to "frame him by any means possible".

The AAP government had in June 2015 constituted a fact-finding committee to probe alleged irregularities in scam. In June 2016, a report obtained from the committee was sent to the then LG Najeeb Jung after which an FIR was registered in the case.

The Rs 400-crore water tanker scam is about the alleged irregularities and favouritism in hiring private tankers by the Sheila Dikshit government in Delhi to supply water to the areas which did not fall under Delhi Jal Board's network.

The irregularities are said to have happened in 2012 during previous Congress government in Delhi.