The CBI has collected documents from the ministry of corporate affairs about companies which were granted spectrum allegedly in an arbitrary fashion between September 2007 and January 2008.
According to CBI sources, the MCA documents deal with the shareholding of the company and the investments brought in the firms from abroad.
The documents include list of shareholders and whether there was any set of directors during the time of grant of spectrum who could have influenced the issuance of licences.
Among the companies whose documents were taken for examination included Reliance Communication, Etisalat-DB led by D Balwaa, Loop Telecom and Unitech-owned Uninor.
E-mail requests sent to these companies for reaction remained unanswered.
The CBI had searched some of these companies last year in connection with the Spectrum issue and claimed to have seized documents related to alleged irregularities in allocation of 2G Spectrum to some of the new players.
The CBI registered a case against unknown Department of Telecom officials and unknown private persons and companies charging them with criminal conspiracy and corruption under the Prevention of Corruption Act last year.
Ever since the licences were issued in 2008, there has been widespread criticism and claims that there could have been loss of thousands of crores to the exchequer on account of irregularities.
The CBI had searched offices of Wireless Planning Cell (WPC), the department responsible for allocating spectrum, and the office of Deputy Director General (Access Services) of the Telecom Ministry to probe the allegations of connivance of officials with private companies in allocation of Spectrum.
"It has been alleged that there had been serious irregularities in the award of Unified Access Services Licences to private companies.
"As per information received, there was criminal conspiracy between certain officials of DoT and private persons and companies in order to award licences to these companies by putting a cap on the number of applicants against TRAI recommendations," CBI said in its FIR.
It also said the licences had been awarded to private companies on first-come-first-serve basis on the rates of 2001 without any competitive bidding.