Highly-placed sources claimed that till date not a single piece of evidence has been unearthed against Talwar. At the same time, the needle of suspicion was pointing towards the alleged involvement of Rajkumar, a domestic help of a family friend of the Talwars and Talwar's assistant at the clinic -- Krishna. Dr Talwar is currently in judicial custody.

The sources said Talwar getting a clean chit in the case was not ruled out as none of the evidence had pointed to either his or his wife Nupur Talwar's involvement in the sensational case that has attracted nationwide attention.

"We do not go by the media trial. We have conducted our investigations in the most scientific manner and this case was unique in its own way as there were no eye-witnesses," a senior CBI official said on the condition of anonymity.

The sources pointed out that CBI officials simulated the possible sequence of events on the night of the crime to ascertain whether the Talwar couple could have heard the screams of Arushi. The statement by Arushi's parents that they they did not hear her screams appeared to be correct.