A joint team of CBI and Enforcement Directorate will visit Mauritius next month to follow the money trail in the 2G spectrum scam.
Another team of investigators will travel to Cyprus soon to find out transactions routed through that country in several telecom companies allegedly involved in the scam.
A real estate company, accused of being involved in the scam, had allegedly registered several subsidiaries in Cyprus, considered to be a tax haven.
The move is necessitated as the agency will have to file its final chargesheet by May 31, a top CBI official said.
The CBI officials are also focusing on two other telecom firms -- S Tel and Loop, which may figure in the next charge sheet to be filed by the agency. Reliance Telecom has already been named as an accused in the first charge sheet filed by it on April 2.
The agency hopes that it will get a detailed picture of transactions routed through these two countries, the official said.
In its first charge sheet, the CBI has named one of the executives of Reliance Telecom, Gautam Doshi, as an accused and alleged that he was involved in "structuring and funding" Swan Telecom and Tiger Traders (the associate company of Reliance ADAG, which has equity in Swan) and other companies.
The agency has alleged that decisions regarding transfer of funds to Tiger Traders/ Swan Telecom were taken by him.
It is also alleged that Swan was being controlled by another group through a company Delphi Investments in Mauritius.
The agency has also, through Letters Rogatory to Mauritius, sought details of stakeholders and beneficiaries in Delphi Investments.
The CBI is probing whether Delphi Investments to which Reliance Telecommunication had sold its 9.9% stake in Swan Telecom was a front for the conglomerate, the official said.
In its second charge sheet filed yesterday, the CBI named Tamil Nadu Chief Minister M Karunanidhi''s daughter Kanimozhi as a co-conspirator in the 2G spectrum scam and the DMK MP was summoned to appear before a court on May 6 and she faced the possibility of arrest.