The CBI has registered an FIR against former Delhi deputy chief minister Manish Sisodia and others in connection with the Delhi Government's Feedback Unit (FBU) which was allegedly doing political snooping, officials said on Thursday.

The agency has booked Sisodia, a 1992-batch IRS officer Sukesh Kumar Jain who was then secretary of vigilance, retired CISF DIG Rakesh Kumar Sinha who was working as special advisor to Chief Minister Arvind Kejriwal and joint director in FBU, they said.