Guys,
JD cannot be the murderer. After Avni died and Anjali was accused of the murder, Addy was very happy and raving about JD's success. She tells JD that he is brilliant as he has hit the target in such a way that not only is Avni out of the way but so is Anjali!!! That is when JD informs her that he didnt kill Avni and Anjali is shocked..She tells JD that If she didnt kill Avni, he didnt kill Avni and Anjali too didnt kill Avni, then who could have done so?
So, If the writers show that the murderer was JD then, they have forgottent his scene!!