The certificate was cancelled on July 31 by the State Level Schedule Caste Scrutiny Committee(SLSCC) after a series of hearings and a notification in this regard would be published soon, the sources said.
Das represents Salgara assembly constituency in Gomati district.
Both RSP and Das could not be contacted for their reaction.
The Leader of the Opposition, Ratan Lal Nath said his party Congress had long been demanding cancellation of Das' SC certificate in the state assembly and the government had appointed a committee to investigate the allegation, but it took more than four years to complete it.
Das, he said, should be immediately expelled from the assembly and all legal action should be taken against him for indulging in forgery.
Tripura Tapasili Jati Surakhsa Samity (TTJSS), which placed many evidences against the RSP MLA with the SLSCC, in a press release during the day also demanded legal action against him for enjoying the facilities available only to the SC.