Reacting to a report in a national daily that claimed that the United Progressive Alliance (UPA) government "vetted" the coal blocks allocations probe status report before it was submitted to the Supreme Court, BJP leader Sushma Swaraj said this was a "very serious matter".
"This is evidence of the government's pressure on CBI to save the prime minister," Sushma Swaraj said on Twitter.
The news report said the Central Bureau of Investigation (CBI) probe report, submitted last month, had been vetted by Law Minister Ashwani Kumar and officials of the Prime Minister's Office.
It further said that senior CBI officials, including Director Ranjit Sinha, were summoned by Kumar days before the status report was filed.
During the meeting with Kumar, several amendments in the status report were suggested and some also incorporated by the CBI, the newspaper report held.
BJP leader Arun Jaitley told reporters the newspaper report showed that the government would not allow the CBI to carry out its work with honesty.
"CBI's image of an independent agency is now completely demolished and dismantled. CBI cannot go to the root of the matter and find the truth, and even if some honest officer tries to find the truth, the UPA is a rogue government which will not allow it to act independently," he said.
"Therefore the system will have to seriously consider whether an SIT must take over the administration and investigation of coal scam," he said.
Jaitley said the search for truth has now been interfered with, and this was being done at the level of minister and Prime Minister's Office (PMO) officials, raising serious questions.
"The UPA is interested in diluting the guilt of culprits. What dilutions are to be made in the report -- that was the agenda of this meeting," he said.
The BJP leader said interference in CBI's work has been prohibited by an apex court ruling.
"In a case related to autonomy and independence of CBI, the Supreme Court categorically had said, quoting from an English principle, that no minister of government can interfere and tell the CBI what to do and what not to do and that is now completely violated," Jaitley said.
"The coal scam clearly shows that allocation of coal was tainted, and it was a case of nepotism. The power plants of the country are starved of coal and favourites of this government were allocated coal mines, and actual mining has not begun," he said.
Jaitley said that instead of restoring natural assets back, this government wants to dilute its own guilt, and that of those to whom allotments were made, by interfering in a due process of law.
"The government owes an explanation. Persons named in the report should publicly speak whether this is true or otherwise. The original unaltered report of the CBI must be made public and also placed before the SC," he said.
India's official auditor had last year revealed that the lack of transparency in the allocation of coal blocks to private players resulted in the loss of a whopping Rs 1.85 lakh crore($37 billion) to the exchequer as on March 11, 2011.
The audit report does not directly indict the prime minister or his office. But during the time these mining blocks were allotted, the coal portfolio was held by Manmohan Singh (between July 2004 and May 2009).