Arvind Kejriwal has claimed that the CBI raids were targetted at him.
The Central Bureau of Investigation says that it probing five audio recordings recovered from Chief Minster Arvind Kejriwal's principal secretary Rajender Kumar's email, purportedly carrying his oral instructions to allegedly influence contracts in favour of a private company.
CBI sources say that Mr Kumar had initially refused to share his email password to during his detailed examination had later provided the details.
They claim that scrutiny of his email account resulted in discovery of five audio recordings pertaining to the period of 2011-13 which carry his purported instructions to the officers handling tenders and contracts to allegedly manipulate and favour Endeavour Systems, which is also named in the First Information Report.
The voice samples of Mr Kumar, a 1989-batch IAS officer of AGMUT cadre, have been taken as per legal procedures and matched forensically, the sources claimed adding that the said conversations could bring more people into scrutiny.
The CBI said that it has registered a case against Mr Kumar and others on allegations against the officer that he abused his official position by "favouring a particular firm in the last few years in getting tenders from Delhi government departments".
Mr Kumar has been booked under 120-B of Indian Penal Code (criminal conspiracy), and 13(2), 13(1)(d) of the Prevention of Corruption Act (Criminal conspiracy, criminal misconduct etc).
"The accused allegedly facilitated award of contracts worth Rs 9.50 crore (approx) to the said company through ICSIL and misused his official position as public servant. The accused were instrumental in award of projects to the said private company in Delhi Transco Ltd; Health and Family Welfare Department, GNCTD; Delhi Jal Board and Department of Trade and Taxes, GNCTD," CBI had said in the statement after the registration of the case.