CBI Spokesperson Abhishek Dayal said the CBI on Saturday carried out searches at the house of a CBI's Deputy Superintendent of Police, Devender Kumar, who is the Investigating Officer in the Qureshi case, in Delhi.

"An FIR was registered against Rakesh Asthana, Devender and two private persons, Manoj Prasad and Someshwar Prasad, on October 15 following a complaint by Sathish Babu Sana of Hyderabad," the CBI said.

The agency said the amended provision of the Prevention of Corruption Act, which mandates prior approval for initiating probe, won't apply in the case against Asthana.

The country's top probe agency alleged that bribes were taken at least five times in December 2017 and October 2018.

The CBI said it has statement of Satish Sana recorded under Section 164 Cr.PC twice on October 4 and October 20, which completely "corroborates" allegation against Asthana and others.

Sana, in his complaints, said he had been made to part with huge amount of money by CBI officials including Asthana and Devender, on the pretext of helping him in a case, wherein he has no involvement.

"I have made recordings of most of the WhatsApp messages and WhatsApp voice calls which I will produce as and when asked to do so," Sana, the complainant, said.

Someshwar, CBI alleged, handled Asthana's investments.

Asthana, a 1984 batch Indian Police Service officer of Gujarat cadre, is accused of accepting a bribe of Rs 2 crore from a businessman who was under probe in the Qureshi case in order to "wreck" the investigation. The case was being examined by a special investigation team (SIT) headed by Asthana.

The CBI lodged the FIR on October 15 after the arrest of a middleman Manoj, who has given a confessional statement before a magistrate confirming the payment of Rs 2 crore to Asthana.

Manoj has reportedly admitted that he had paid the bribe on behalf of Qureshi, who is being probed by the CBI and the Enforcement Directorate (ED) on charges of money laundering for a host of public servants. Qureshi was arrested by the ED in August last year under the provisions of the Prevention of Money Laundering Act.

Apart from Asthana, the CBI has also named Samant Kumar Goel, Special Director of India's external intelligence agency RAW, but not an accused.

The latest move is another indication of the escalating internal war within the CBI's top officials, Verma and Asthana.

Earlier, Asthana had filed a complaint against the CBI Director accusing him of interfering in the Indian Railway Catering and Tourism Corporation corruption case involving family members of Rashtriya Janata Dal leader Lalu Prasad.

Subsequently, in a press statement, the agency had denied Asthana's charges against the CBI Director and asserted that the Special Director himself was under probe in half-a-dozen cases and was trying to intimidate officials who were probing his role.

High-profile investigator Asthana enjoyed a clout in the CBI as most high-profile cases involving politicians were handled by him. These include graft charges against Lalu Prasad, former Union minister Chidambaram and his son Karti, and the AgustaWestland chopper deal.

The fight between them has raged for several months with Verma allegedly seeking to block Asthana's elevation as special director on the ground that the latter was being probed in some cases. The Central Vigilance Commission (CVC), however, brushed aside the objection, saying that the charges against Asthana were not substantial, a decision which was later upheld by the Supreme Court.

The rift came out in the open once again when the CBI Director objected to the CVC calling Asthana as the CBI's representative for a meeting when the former was abroad on an official trip.