Here are the top 10 updates on this big story:
The CBI's First Information Report (FIR) against Rakesh Asthana is based on the claims of Sathish Sana, a Hyderabad-based businessman investigated in connection with meat exporter Moin Qureshi, who is accused of money-laundering.
Sathish Sana has alleged that he was asked to pay a bribe of Rs 5 crore to Mr Asthana, the investigating officer, to be rid of the case. Manoj Prasad, an investment banker based in Dubai, was allegedly the middleman who asked him to pay this bribe. Manoj Prasad was arrested on October 16 when he was returning from Dubai to allegedly collect an installment of the agreed bribe amount.
The CBI claims to have analysed nine phone calls immediately after the arrest, which, it says, shows panic after Manoj Prasad's brother learnt of his arrest. The calls were allegedly exchanged between Mr Asthana and a senior officer of another intelligence agency, who wanted to confirm details of the arrest.
Nowhere in the statement has Sathish Sana mentioned any direct meeting, interaction or payment of bribe to Mr Asthana. But the CBI says Sathish Sana told a magistrate that he had paid Rs. 2 crore as bribe to Mr Asthana over a 10 month period from December last year.
In a complaint to the government in August, however, Rakesh Asthana alleged that it was the CBI chief who took that bribe in the case of Moin Qureshi, who is being investigated for allegedly channeling illegal money through Dubai, London, and other places in Europe.
Mr Asthana also alleged he was framed for preventing Sathish Sama from skipping the country and pressing him to cooperate with the investigation.
Sathish Sana had, during an interrogation, "admitted" to bribing the CBI director, Mr Asthana said in his letter to the Cabinet Secretariat. The letter listed 10 instances of corruption, criminal misconduct, interference in the investigation of the sensitive cases. Days after this letter, the CBI put out a statement that Mr Asthana's role was being investigating in several cases.
Earlier this month, Mr Asthana also accused the CBI chief of trying to frame him in the case of Sterling Biotech, which is being investigated for loan default.
The CBI infighting started last year when the director objected to the appointment of Mr Asthana, a Gujarat cadre officer, as he was under investigation in the Sterling Biotech case.
Rahul Gandhi tweeted: "The PM's blue-eyed boy, Gujarat cadre officer, of Godra SIT fame, infiltrated as No. 2 into the CBI, has now been caught taking bribes. Under this PM, the CBI is a weapon of political vendetta. An institution in terminal decline that's at war with itself."
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