Central Bureau of Investigation on Tuesday froze four bank accounts of Chennai-based chartered accountant A Krishnamurthy arrested in "cash-for-transfer" scam along with three other persons including R Perumalswamy the personal secretary to former Minister of State for Finance Gingee Ramachandran.

The accounts were frozen by the CBI even as the agency started hunting for his bank lockers. Krishnamurthy, however, maintained that he did not have any locker.

Agency sources said it has got some leads, which were being further pursued. They, however, did not elaborate any further.

After his arrest, Indian Revenue Service official Anurag Vardhan reportedly told CBI that he wanted a transfer to Mumbai for his chidlren as they wanted to undergo treatment in the metropolis.

However, after the CBI checked his official record, it was found that Vardhan had cited similar reason for his transfer from Mumbai to Delhi last year, official sources said.

Vardhan was selected for IRS in 1994. He later went for training to Mussoorie for 18 months and from there to Chennai where he continued till 2001.

CBI sources said Krishnamurthy's interrogation pointed towards the alleged involvement of some officials of the finance ministry, who were instrumental in passing transfer orders after receiving illegal gratification.

The sources said "chits" with names of some officials and desired postings, recovered from the residence of Perumalswamy, were being examined.

The sources did not rule out the possibility of quizzing Ramachandran, who had to resign last week.

Another person, Padmanabhan, a project associate at the Centre for Atmospheric Science, Indian Institute of Technology, Delhi, who is alleged to have driven Perumalswamy to the residence of IRS official Vardhan and was present when the money changed hands is also in CBI custody.

While Vardhan was further remanded to 7 days of CBI custody, Padmanabhan was sent to judicial custody by a Delhi court on Tuesday.