Along with Roshni cobra and her sapola bhai and Aditya, I am very much sure that ND is involved in the murder (I don't know why ,may because of the reasons Raaga gave to us)
It was a very well planned murder and Kiran was already hit by another car when Jai reached the accident spot. Remember the white car passing by when Jai turned his car to Park Road.
According to Jai the car went out of control due to bad weather but it was not raining or raining that hard that could have blurred the vision of Jai (from noticing Kiran or any other person from standing in the middle of the road). Jai is not a furious driver, remember Aditya telling Sahil that Jai is a very careful driver during the trip to the farmhouse.
ND reached the spot as soon as Jai car hit Kiran body; He was there at the spot in a minute as if he was waiting for Jai to arrive at the spot with Roshni. I believe that Roshni's presence there at the spot was deliberately planned to keep a witness to the entire event otherwise how would you trap Jai Walia and she was the one who took him to The Park Road
ND was cursing Jai Walia to make him feel guilty of the crime and spared him and left him at the justice of God so that he feels indebted to him for life, for saving him
ND sends his girls to JAI WALIA, why? Why not Aditya or Roshni or may be Kiran's own family .Fine they disowned her and there was a fear of his girls being rejected by them but how was he so sure the Jai will definitely help the girls.
If it indeed was an accident why did Roshni bribed Sandy .May be he heard her conversation with somebody regarding the plan. If it was just an accident than Jay surely would have come clean out of it
Now the questions bothering me
Why is Aditya after JAI'S life , it is not for money because after Jai the entire property belonged to his children only, seven years back Bani was not even in the picture, moreover Jigyasa was there to take care of it.
If roshni was to marry Jai, why did she trap JAI in this false crime? She didn't have any reasons to do so. She was marrying him; she would have got everything she could have wanted
Why Aditya never showed any emotions on mention of Kiran's name and why did he sketched his plan with Nishikant Dixit to back stab JAI