Even if krishna is involved in the murder his presence on or before night of murder was not revealed by any talwar family member..
He surely was in with someone permission & knowledge..
Seems both murders were in course to hide somehing fishy that could have spoiled murderers future.
If Mr.Talwar was drunk at that night but not Mrs.Talwar.. The accused/co-accused is definately Father/Mother koi aur (which currently in picture is krishna).
