The agency had registered the PE in January this year on the basis of a complaint filed by the Vigilance Department of the Delhi government.
The CBI sources said that no search or raid was conducted at the premises of Sisodia. According to rules, no search or raid can be conducted under a PE.
It is alleged in the complaint that a consultant of a well-known public relations company was hired by the Delhi government to promote "Talk to AK" (Talk to Delhi Chief Minister Arvind Kejriwal) campaign and a proposal of Rs 1.5 crore was prepared for this purpose.
Official sources said the CBI has registered a preliminary enquiry to probe these allegations and is looking into the alleged role of Sisodia and others.