Though the agency would not reveal much, as it might 'impede ongoing investigations', sources said this confession, recorded under Section 161 of the CrPC, could not be admitted in court.

The CBI's main thrust remains on the murder weapon, the hunt for which took officers to the Sector 53 home of Rajkumar, the domestic help of Praful and Anita Durani — friends and business partners to the Talwars. Sources also said a team accompanied Krishna to an undisclosed location in Uttar Pradesh on Tuesday, in search of the weapon. This was hours before he was produced in the Ghaziabad court.

The other bits of ‘evidence’ with the CBI — a ‘khukri’ recovered from Krishna's room last week, and a few ‘suspicious' items picked up from Rajkumar's room on June 13 — are being examined by the Central Forensic Sciences Laboratory (CFSL). Scientific evidence is also being pieced from the lie-detector and narco tests done on Krishna. CBI's Joint Director Arun Kumar told the media on Tuesday: “We are following other clues too.”

However, one fact the CBI can now confirm is that Krishna had been to the Talwars' home on May 15, the day of the murders. He had earlier denied this. Investigating officers said Krishna's fingerprints had been found in the house. Officers have also done a recce of all places Krishna had visited after the murders, and it seeks more help on this from the Noida Police.

Meanwhile, Anita Durani faced a few uncomfortable questions from the agency on Tuesday, with the CBI reportedly capturing her statement on video. She was largely grilled about the movements of Rajkumar.

It is understood that another domestic help working in Jalvayu Vihar, Vijay Mandal, who was picked up for interrogation on Monday, has not been able to give the investigative agency any conclusive lead. The CBI also dismissed rumours that it was picking up domestic helps of Jalvayu Vihar — the latest being one Bharti.