Noida: The Central Bureau of Investigation (CBI) on Friday cordoned off the Noida house of the Talwars and thoroughly checked the overhead water tanks on the terrace and the water pipes to search for the missing weapon with which teenager Aarushi Talwar and her domestic help were murdered a month ago.

According to CBI sources, the agency received an anonymous tip about the murder weapon, now believed to be a khukri, a curved short knife. The Noida Police had earlier said the murders were committed with a surgical knife.

The probe agency officials were accompanied by a forensic team from the All India Institute of Medical Sciences when they visited the house of the Talwars in Jal Vayu Vihar.

Aarushi's dentist father Rajesh Talwar is under arrest for alleged involvement in the May 15 night double murders.

Meanwhile, another CBI team visited the house of Anita Durrani, a dentist colleague of Rajesh Talwar with whom he was allegedly into a relationship.

Three people involved

CBI sleuths conducted a thorough search of the Noida home of the Durranis and sealed the room of their servant, Raj Kumar, who is under CBI custody. They questioned Anita and her husband Praful Durrani once again.

The CBI had visited the Durrani house late on Friday night too and interrogated the servant, who was close to Hemraj, the murdered domestic help of the Talwars.

According to CBI sources, Raj Kumar had mentioned that three people were involved in the murders of Aarushi and Hemraj.

CBI sources said more arrests are likely in the sensational case. CBI Joint Director Arun Kumar, who led the search in Talwar's residence, tried to recreate the timing of the crime. He went from the home of Krishna to the Talwars' through the terrace.

The investigators also questioned guards, security supervisors and a garbage collector. Talwar, who is in Dasna Jail in Ghaziabad, is to be put through a psychological test again to "reconstruct" the crime scene. He underwent a similar test Friday.

Krishna was produced in a CBI court in Ghaziabad yesterday afternoon. His family had Friday approached the National Human Rights Commission to protest against his detention and also visited the Nepal embassy in New Delhi. The CBI has sealed his house.

Aarushi Talwar was found dead with her throat slit in the bedroom of her flat in Jal Vayu Vihar on May 16. At first domestic help Hemraj was suspected, who was found dead as well later.