The CBI has conducted searches at 12 locations in eight cities of Maharashtra, including at the premises of ACP Sanjay Patil and DCP Raju Bhujbal, in connection with allegations of corruption against former state home minister Anil Deshmukh, officials said on Wednesday.

The searches were carried out in Mumbai, Pune, Ahmednagar, Nashik, Thane, Solapur, Sangli and Osmanabad, they added.

The premises of "encounter specialist" Patil in Pune and Mumbai, and those of Bhujbal in Ahmednagar and Mumbai were covered during the operation, which concluded on Tuesday night, the officials said.

The other premises belonged to alleged middlemen whose names have not been disclosed by the agency.

The Central Bureau of Investigation (CBI) has booked Deshmukh and other unidentified persons under the IPC section related to criminal conspiracy and sections of the Prevention of Corruption Act for "attempting to obtain undue advantage for improper and dishonest performance of public duty".

In his letter to Maharasthra Chief Minister Uddhav Thackeray after he was removed from the Mumbai police commissioner's post, Param Bir Singh had alleged that Deshmukh asked Assistant Police Inspector Sachin Waze to extort over Rs 100 crore a month from the bars and restaurants of the city, the officials said.

"The preliminary enquiry prima facie revealed that a cognizable offence is made out in the matter, wherein the then home minister of Maharashtra, Anil Deshmukh, and unknown others have attempted to obtain undue advantage for improper and dishonest performance of their public duty," the CBI FIR alleges.

According to the CBI manual, a preliminary enquiry is initiated to assess if there is enough prima facie material in the allegations to proceed with a regular case for a full-fledged probe, the officials said.

The CBI enquiry found that Waze was reinstated into the police force after being out of service for more than 15 years.

Waze was entrusted with most of the sensational and important cases of the Mumbai City Police and Deshmukh, the then Maharashtra home minister, was aware of it, the FIR alleges.

It further alleges that Deshmukh "and others" exercised undue influence over the transfer and posting of officials, thereby exercising undue influence over the performance of their official duties.