Some local people today spotted dogs pulling a sack, containing human bones, in a dried up pond at Mirbazar locality behind the party office.
The police took away the sack and a case has been registered, the sources said.
A number of CPI(M) leaders and workers, including MLA and former minister Sushanta Ghosh, were named accused in a murder case following recovery of skeletons at Benachapra in West Midnapore district in 2011.