Rai, who has been critical of former Prime Minister Manmohan Singh in the context of 2G and coal scams, said that the control structure of CBI makes it vulnerable to becoming an "easy game" for various allegations and speculations.
"It is true that a police dominated investigative agency cannot enjoy the kind of autonomy or independence offered to the Election Commission or the CAG..." Rai has written in his book, 'The Diary of the Nation's Conscience Keeper -- Not Just An Accountant'.
The book, in which Rai talks about his experience as the Comptroller and Auditor General (CAG) of India during 2008-2013, has incidentally come amid a long-running debate on independence and autonomy of CBI, while a controversy has also erupted about alleged meetings of current CBI chief Ranjit Sinha with those linked to entities under its probe.
While observing that successive governments and various political parties have always been critical of CBI, Rai said that none of them actually took any "steps to correct the CBI's administrative control structure when they come to power".
"It can certainly be decoupled from the direct control of the Minister for Personnel or the Prime Minister. Such a move will not only lend a great degree of credibility to the initiating government, but will also help establish an agency with professionalism and integrity of its own," he said.
In the 267-page book, Rai further said that CBI has always been blamed by the political parties to be a "handmaiden of the government in power" and of being misused for "narrow political ends".
"The CBI, unfortunately, gets caught in the crossfire. Being an executive agency functioning in the Department of Personnel -- which is directly under the Prime Minister -- makes it vulnerable to speculations," he said.
Observing that the current structure of CBI makes it
vulnerable to speculation, Rai said in such an administrative bind, "the agency becomes easy game for a Law Minister to 'correct its draft affidavits'".
"... It (CBI) is exposed to allegations of reopening investigations whenever a political ally or opponent begins to flex its muscles, and of 'fixing' inconvenient officers against whom cases can drag on for decades without even a charge sheet being filed".
"These issues made the Supreme Court comment that the CBI is a 'caged parrot' without the freedom to investigate or administer," he said.
Rai's loss estimates in 2G spectrum and coal block allocations during the previous UPA government had raised huge controversies.
During Rai's tenure, CAG came out with reports that alleged irregularities in 2G spectrum and coal block allocations, and Commonwealth Games, 2010.