In which case did the Supreme Court observe that the Central Bureau of Investigation is a 'caged parrot'?

During the hearing of the coal-block allocation investigation on 8 May 2013, the Supreme Court described the CBI as a "caged parrot", criticising political interference with the probe. The remark was therefore made in the "Coal-gate Scam case". Vineet Narain v Union of India (1998) dealt with CBI independence in general, and the 2G and Railway Board bribery matters were different proceedings.