I watched today's episode quite closely. Now i am confirmed that the murderer is male not female because at 12:44 jhanvi tells something that will rule out the murderer as female. Now she is speaking about after marriage she thought everything would be fine but instead he made things worse, she tells she trusted that person but that person took away ashwin from her. She also tells that person wanted to prove her mad by telling ashwin's ghost wants to talk to her and what wrong did she do to him. Ok the show wants its viewer to guess arjun and maya clearly. But i dont think maya as murderer strongly for three reasons; it would be an easy guess for viewers; the murderer is male according to jhanvi and the third reason is: if maya was a murderer she would not call her(maya) to expose about the killer in go down for first and if maya was a murderer once jhanvi sees and speaks to the killer (maya who is present there) she would try to run away from that go down but instead she faces the murderer twice at go down thinking that she would expose the killer but she could not tell maya as arjun is also present there; arjun along with maya would think that she is having hallucinations only option she had would be saanjh to tell about the murderer alone .Arjun couldn't be the killer again for 2 reasons: it wold be an easy guess for viewer; again jhanvi would try to run away from that go down instead of facing the murderer twice. No other characters in beyhad have such relations with jhanvi which she tells to the murderer in go down. I smell something fishy here.
Here is my theory: I think that maya isn't a legit child of jhanvi, so ahwin would really torture maya in her childhood(i think even maya doesn't know about her real father). Now maya's real father might be the reason as well ashwin separated from maya. There is third person in beyhad who might be linked to jhanvi which they haven't shown yet and by the way he might be a doctor (killing ashwin with an empty syringe). The marriage she's speaking about might be about that person and he would leave maya and her. But that person might be obsessive about maya like maya is with arjun. Maya doesn't know about him but everywhere she would be followed by her (priest killed in Mauritius)
Jhanvi always says sorry to ashwin's picture because when she had reached ashwins house with a pistol and when ashwin tries to defend him and attacks jhanvi maya"s real father might have come in the middle and inject him with an empty syringe while jhanvi watches him hopelessly. So actually jhanvi is the only one who knows the real murderer of ashwin from the beginning and it is someone who she doesn't want to expose because it would reveal everything between him and that person
By the way jhanvi also wants to call maya alone in the go down to expose the murderer and she also tells what story began with that go down she wants to end that story there.There's got to be some event linked with that go down.
I really thought about the murderer and came up with this theory. i strongly believe there might be third person who might be an obsessive father of maya so that nothing bad happens to her and maya thinks that god has favoured her all the time.