Devesh Chakraborty is a close confidant of arrested private promoter Ayan Sil.

Chakraborty, whom the CBI believes was the middleman between Ayan Sil and middlemen in the case, has been asked to appear at the central agency's Nizam Palace office in central Kolkata by Monday afternoon.

He has also been named as a co-accused in the chargesheet filed by the central agency in the special CBI court last week, sources said.

Preliminary investigation revealed that Chakraborty was the last point of contact between eligible candidates willing to pay for jobs and an outsourced agency owned by Ayan Sil for recruitment in various municipalities.

Sources said such candidates were first introduced to Chakraborty, who recommended the candidates to Ayan Sil for consideration after sealing the deal.

The CBI has secured the names of some candidates who got jobs following Chakraborty's recommendation.

Sources said some of them were interrogated by the CBI and officials got information from them about Chakraborty.

The investigation revealed that recruitment for medical officers, ward masters, clerks, drivers, assistants, sanitation assistants and other posts in several municipalities was done in exchange for cash.

In the charge sheet, the CBI had pointed out how similar questions were set for written examinations to grade posts to make room for candidates who paid for jobs.

The inquiry revealed that instead of employing the expertise of any particular agency in this regard, the job of preparing question papers for various posts was given to an agency owned by Ayan Sil.