On any normal night, the headquarters of the CBI is steeped in silence with only alert sentries of CISF seen guarding the imposing building, but Tuesday night was different.
Around 10 pm, teams of about 15-16 officers entered the compound in Innova and Ertiga cars, sources said.
A white sedan followed with M Nageswar Rao, who was given charge of duties and functions of CBI director.
History was made as no director of the agency was changed in such manner.
A 1986-batch Odisha cadre officer, Mr Rao went straight to his office and took charge of the position around 11.30 pm as rest of the CBI staff was clueless about the changes taking place in the agency.
Alok Verma, who was director till then, had left the building earlier around 7.30 PM which is the normal routine.
He had earlier visited his North Block office during the day as an unprecedented tussle with his deputy, Special Director Rakesh Asthana, had reached the court.
Mr Verma remained in the North Block office till afternoon and left for lunch keeping a tab on local court proceedings where the CBI was strongly arguing to get the custody of its own Deputy SP Devender Kumar on charges of "extortion" from a businessman being probed by him, the sources said.
He was seeking information on the developments of the Delhi High Court where Mr Asthana had approached seeking quashing of FIR naming him. A similar petition was also filed by Mr Kumar.
In the evening, in Satarkata Bhavan, the Central Vigilance Commission was holding a crucial meeting which had to decide the fate of two feuding officers of the CBI -- Mr Verma and Mr Asthana -- who had levelled allegations of corruption against each other.
Mr Asthana was booked by the CBI on October 15 in a case of corruption.
After going through available documents, the CVC in an unanimous decision recommended divesting all the powers of Mr Verma and Mr Asthana.
The recommendation was sent to the government around 8-8.30 pm, the sources said.
On the basis of the recommendation, the Appointments Committee of the Cabinet handed over the charge of CBI Director to Joint Director Rao as "interim measure".
After completing formalities of taking charge, Mr Rao directed the officials to take charge of all the crucial files as sought by the CVC and to ensure no material is tampered with.