Kolkata, Dec 22 : The Enforcement Directorate (ED), probing the multi-crore municipalities recruitment case in West Bengal, has come across a mysterious WhatsApp Group which, it believes, hadf acted as a key medium of information exchange related to the case. ED sources said that while the admin of the WhatsApp Group is Ayan Sil, the private real estate promoter who is currently in judicial custody following his alleged links with the multi-crore cash-for-school-job case, the members of the group were different top office bearers and officials of the those municipalities where those recruitment municipalities have allegedly taken place. Sil is the common link between the school job and municipalities' job case, as during the raid and search operations at this residence last year in connection with the school job case, the ED, for the first time, got evidence of the development of municipalities' job recruitment as well. Sources aware of the ED's findings about the mysterious WhatsApp Group said that preliminary investigations have revealed that the names of the candidates paying money to be shortlisted for selection. However, they believe that the deleted messages in the WhatsApp Group might contain some more crucial information that might help them in framing water-tight charges against the offenders. Now, sources added, the investigating agency sleuths are trying to figure out whether there are existences of similar other WhatsApp Groups that acted as medium of information exchange in the alleged multi- crore scam. So far Sil has admitted in interrogations that the municipalities' recruitment irregularities started as early as 2014. At that point of time, ABS Infozone, an entity owned by Sil, used to act as an outsourced agency for recruitments in the lower level posts in different municipalities. /IANS