Krishna will be produced before the CBI special court in Ghaziabad Saturday.

Rajesh Talwar's sister-in-law Vandana said: "We are happy with the CBI investigations and believe that they have arrested the right person. We are waiting for the truth to come out so that the family gets justice."

Asked if she could pinpoint the motive behind the double murders, she replied: "We would like the CBI to come to some conclusion."

Rajesh Talwar's lawyer Pinaki Sharma, who has vociferously declared the dentist's innocence, said: "We are hopeful of arguing for his bail (in a Ghaziabad court June 26). The CBI believes a 'kukhri (a curved knife) was used in both the killings. Now the CBI must not oppose Rajesh's release."

Krishna apparently also took the name of a friend, who works as a domestic help in the capital. He was also being questioned, sources said.

A CBI team Friday also conducted a psychological test on Rajesh Talwar at the Dasna jail in Ghaziabad where he is lodged. The test was conducted to "synchronise" the sequence of events leading up to the crime, a CBI source revealed.

The agency is also investigating the role of two former servants of the Talwars - Vishnu and Raju. While Vishnu, who was a suspect earlier, is being questioned, Raju was picked up from Mansarovar Park, Shahdara in East Delhi, on Wednesday.

Raju, or Nimraj Kaushal, was believed to have died in an accident at Pandav Nagar area of east Delhi on April 14. However, it turned out to be case of mistaken identity.

Meanwhile, Krishna's family Friday petitioned the National Human Rights Commission (NHRC) for his immediate release.