I think Abhishek is the one who killed Gujral because the person behind the mask is a male.And savitha knows about it and is supporting him. Guess she is the one leaking information to Abhishek.
This whole thing about Gautam is going to be another fake like Nandini.What Gautam mentioned about a person going downstairs while vase broke is going to be true.
Savitha after knowing the truth about Abhishek will go mad and will repent and eventually be killed by Tulsi.