In a stunning twist to the long and still-unspooling saga of Niira Radia tapes, CBI told the Supreme Court on Tuesday that some officers of the income tax department connived with the former corporate lobbyist to help her dodge hundreds of crores in taxes by fudging documents.

This jaw-dropping charge by CBI on the basis of the scrutiny of just 18,000 of the 72,000 calls of Radia that it has been asked to look into, is part of a classified report that additional solicitor general Paras Kuhad submitted to a bench of Justices G S Singhvi and V Gopala Gowda.

The court reacted to CBI's claim by saying it would monitor this particular aspect of CBI's investigation into the Radia tapes. "It clearly reflected criminality," the bench said. Significantly, additional solicitor general L Nageshwar Rao, who appeared for the I-T department, also said the CBI's secret report pointed to connivance between I-T officials and the former lobbyist they were supposed to be investigating.

"The October 4 report of CBI reflected that contents of three calls, which indicated that they (officials) were hand in glove with Radia. All of them pertained to certain transactions," Rao said. "Now, we will give all the records to CBI," he added.

The Radia tapes are a cache of conversations which were intercepted by the I-T department on the ground that the former lobbyist was involved in illegal activities and, therefore, needed to be probed.

According to CBI, I-T officials in question helped Radia dodge tax demands by making what in I-T department's parlance is known as "accommodation entries". Accommodation entries in this case allegedly involved showing fictitious loans in Radia's account books to camouflage her illegally earned money and, thus, minimize her tax liability, besides legitimizing her "black money".

Though the law officers and the bench did not specify the amount involved, sources said accommodation entries involved a huge amount, with the agency finding 130 accommodation entries I-T officials made to help Radia avoid paying taxes on her several transactions.

The bench said, "Investigation into this aspect has to be swift as already there has been considerable delay. No point in delaying it any further." Adding sarcasm to anguish over the manner in which the I-T department slept over the highly sensitive issue, the bench said, "Nobody has an idea when the intercepts were scrutinized (by the I-T department which put Radia's telephones under surveillance). Everything has happened accidentally!"

However, it returned to its stern self and asked CBI how much time it would require to complete "listening" to Radia's telephone intercepts. CBI said it would require three months to complete the task if it got the services of 10 I-T officials with a joint commissioner level officer to supervise their work. The bench asked Rao to give the names of officials to be involved in the job.

The bench fixed October 18 for passing orders on constituting the team that will listen to the intercepts and said the team would not be changed, be it for promotion or transfer, till the task was completed.

The I-T department had tapped Radia's telephones after the finance ministry received a complaint against her. The department got the home ministry's permission to intercept her telephones for 120 days beginning August 20, 2008. It secured a fresh nod in May 2009 for an identical period.