While the scientific tests conducted on suspects Krishna and Rajkumar in Bengaluru recently helped the CBI obtain vital clues, it was the narco-analysis test conducted on Vijay Mandal alias Shambhu, a domestic help of one of Dr Rajesh Talwar's neighbours, that went a long way in helping the agency crack the case. Dr Rajesh Talwar, Aarushi's father, was released on bail on Friday after being initially named the prime accused in the case by the Noida police.

Rajkumar confirms revenge was motive

Shambhu's name first cropped up when Krishna was subjected to a narco-analysis test in Bengaluru around two weeks back. Although Krishna did not pin-point exactly who Shambhu was, the CBI discovered who he was.

The CBI brought him to Bengaluru and subjected him to a narco-analysis test a few days before Rajkumar's test. During his test, the CBI secured a clear picture on who committed the murder and the motive. Shambhu said Krishna had a problem with Dr Talwar as the dentist had shouted at him at the clinic three days before the murder. He, like Krishna and Rajkumar, mentioned that the main motive was to take revenge against Dr Talwar. He further stated that Krishna slit Aarushi's throat with a khukri. Hemraj was killed after he developed cold feet and threatened to expose the others.

How and why Aarushi & Hemraj were murdered

Rajkumar, in his narco-analysis test, confirmed what Shambhu told interrogators during the test.

Meanwhile the Central Forensic Science Laboratory, Hyderabad, has sent its report to the CBI regarding the T-shirt belonging to Rajkumar. Sources told rediff.com that the report states that the bloodstains, which were found on the T-shirt, were not Rajkumar's.

The CBI will now take blood samples of the accused as well as the deceased and get it compared to one found on the T-shirt.

Coverage: The Aarushi murder case