The CBI is likely to register more than one FIRs in the alleged irregularities in allocation of coal blocks after it came across several cases of violation of norms by state government officials and allottees.
The agency has already questioned senior bureaucrats who were overseeing allocation of coal blocks during 2006-09, CBI sources said.
Meanwhile, the agency is also taking into cognisance the Comptroller and Auditor General report on alleged coal block scam which was tabled in Parliament on Friday.
The sources, however, made it clear that CBI would not be going into policy issues but will limit its role to aspects where criminality could be established.
The agency has also questioned members of screening committee including Secretaries and Joint Secretary in the Ministry, CBI sources said.
They said the questioning of the Coal Secretaries, who also chair the screening committee, was done to understand the issues involved in the allocation of coal blocks during the period and so far agency has not found any irregularity on their part.
The agency has shortlisted nearly 15 companies which allegedly violated norms of allotment of coal blocks and questioning of their officials is going on, they said.
The agency has registered the Preliminary Enquiry (PE) , which is the first step of initiating the CBI probe, against unknown persons in connection with a complaint referred to it by the Central Vigilance Commission.
Allocation of coal blocks is done through an inter-ministerial inter-governmental body called the Screening Committee chaired by coal secretary.
It includes the secretaries of nine ministries having interests in coal, besides heads of various PSUs, and chief secretaries of coal-supplying states.