Everything is Beyhadh suspicious right now but I have feeling cat will be out of box very soon. The reason I am saying this is because culprit is way too sharp and has eye on everybody's movement. The killer's motive looks more like revenge than murder to somebody.
The killer is not someone;
Who would threat in publics (Arjun)
The very important factor of people who are mentally disturbed, aggressive, those people are only capable of attacking not killing. This is where big difference is in harming and killing a person (Maya Mehrothra)
Killer is someone
Would never leave their clues behind and rather take advantage of other's anger
The person who shows beyhadh loves can also hold immense hatred at one point (Vandana)
Plays cards very carefully and kill somebody like slow poison (Arjun)
Arjun : Very recently, I have noticed his expression but that does not make him killer. His face clearly shows his intentions are different rather than killing. If his motive is capturing property than by now he would have hurt Maya in some way. His motive is bigger than we would have thought in our dreams (there is always some evilness behind an innocent face)
Maya : Even if she stands on roof and shouts she killed Ashwin nobody would believe her because law would never get proof against her like Jhanvi and Arjun. The Maya we were introduced is someone who does not leave her stains behind on anything she does.
Jhanvi : One of the important person who is only witness to everything happened right from Maya's childhood to Ashwin's death. Her actions and words are always different. She could have easily texted Saanjh on her phone but we are only seeing what they showed. Her face is not terrified but is more concerned about something drastic.
PS : Whoever the killer is will be out soon but not in jail. The troublesome will lurk around till the past is not buried under ground forever. To save present and future, past has to come in front of mirror.