Who was blocking FIR against bigwigs ?

FIR against ex-Chief of ICICI and one Businessman and sudden transfer of an SP from Delhi to CBI, Ranchi has raised many questions. It is said that when boss asked the SP why any action has not been taken in the case for the last few months, the SP reportedly said that it was because of senior officers alleged instructions. Now the question is who was interested in blocking the case and who allegedly leaked the info ?