Narco test revealtions are admissible as evidence in court in India yet. It only aids in proper investigation, when the information is scarce and the suspects do not provide correct information. The CBI will still have to get a confession in front of a magistrate if the case is to be solved on the basis on confession.
In this case, two persons are dead. The tests on parents have so far not yielded anything so far. The others who provided conflicting evidence are subjected to the test. The analysis of the blood stains on the shirt is on. We will know soon if they belong to Arushi or Hemraj's blood group.
The biggest mistake of the Noida police was allowing the place to be cleaned up. If Krishna is involved, he really would have blessed his stars, and done a very good job of cleaning the place. Had the place been sealed they could have got finger prints (which is still possible), on the glasses, door handles, etc.
