The Supreme Court today expressed displeasure over the tardy pace of probe by the Income Tax department into the tax evasion cases linked to 2G spectrum case, saying it wanted "results".

A bench of justices G S Singhvi and A K Ganguly directed the department to file a detailed report on action taken by it during the last three years when it got a complaint in this regard and began tapping corporate lobbyist Niira Radia's telephone.

"The IT department must be quicker. This is not a normal case of tax evasion. It (probe) should have been done fast. These are not ordinary cases to be handled in ordinary way," the bench said.

The department, however, defended its ongoing probe saying that the investigation has entered the "fifth layer" and the approach towards the case has not been tardy.

The court, however, was not satisfied and said, "We are not concerned about layers but results."

The bench allowed the IT department to approach the special judge, trying the 2G case, to interrogate company officials who are in judicial custody for their alleged role in the scam.

The bench also agreed to hear a plea by petitioner, the Centre for Public Interest Litigation, for appointment of two independent persons to assist the court in monitoring the probe by various government agencies in the scam. The CPIL had made the plea alleging that "big players are being let off".

The court also assured the petitioners, CPIL and others, that all the persons involved in the scam will be brought to justice irrespective of their wealth, position and power.

"You (petitioner) rest assured that no person, irrespective of their chair and wealth, could get immunity in any way," the bench said, adding "investigation in the case has made some progress which would not not have been possible in normal circumstances."

CBI, meanwhile, contended that no person would be let off as investigation is still going on against Reliance and Tatas for their involvement in the scam.

The investigating agency also submitted that it will file fresh status report on the ongoing investigation in 2G scam after the summer vacation.

The court after hearing all sides posted the matter for further hearing on May 13, when it would delve into the plea for appointment of independent person to assist the court in monitoring the probe.