The CID has summoned Trinamool MP Abhishek Banerjee for a second round of questioning on Sunday. The first session, on Thursday, lasted about five-and-a-half hours.

Abhishek has been directed to appear at the CID headquarters in Bhabani Bhawan. “The questioning will begin from where they left off,” a police officer said.

The CID is probing an allegation that the signatures of Trinamool MLAs were forged on a document submitted to the Bengal Assembly nominating Sobhandeb Chattopadhyay as leader of the Opposition.

“Abhishek has been asked to appear for a second round because we want to clarify a few things,” a senior officer said.

CID insiders said the location of the original resolution book, a copy of which was sent to the Speaker, is still unknown. Abhishek apparently couldn’t recall where it was on Thursday.

Sources said Abhishek told investigators that the signature bearing his name was his own. But he couldn’t answer when asked who all had signed on behalf of some of those MLAs who told the investigating agency that their signatures attributed to them were not theirs.

The CID has visited several Trinamool MLAs and engaged a handwriting expert to analyse signatures.

“The original resolution book is a vital piece of evidence in the case. An investigation into alleged fraud, cheating and criminal breach of trust relies heavily on original documents,” an officer said.

A copy of the “Meeting Resolution Book”, bearing signatures of 70 Trinamool MLAs, in CID’s possession, lists the signatories.

On Friday, Abhishek said: “I have been asked to appear again on June 14. I will be in Calcutta... and will appear again... I have never evaded summons, be it by any investigating agency. I have met interrogators in Delhi. In Calcutta, I have met them at the Nizam Palace or CGO Complex. I have always cooperated with an investigation.”