Dear Padmini
Thanks for your detailed response. I agree that the mobile phone and murder weapon are vital clues in this case. Its believed the CBI even searched the drains of the locality in search of the murder weapon. This gave some relief to the neighbours as the municipality was not removing the blockages in the drains despite their best efforts.
I think Narco test was conducted on both Dr Talwar and Hemraj, But the test proved inconclusive and it is believed that Hemraj introduced a new person in his narco report.