Is there a sigificance of the knife?

Some time back JC made a post that the person who killed Ayesha may not be PPP. I too think there could be a third person involved here, most likely Ranvir. What if he comes there later and uses this knife to kill PPP. Since Prachi's finger prints are on it, Prachi could get implicated. As far as the case against Milsi is concerned there is a big drawback which I am surprised his lawyer did not point out - there appears to be no motive to kill her. Granted Ayesha had done a lot of bad things and had come between him and his wife but why kill her when everything has gone back to normal and Ayesha herself seems to have changed? The prosecution's case is therefore weak.

Whereas if Prachi is implicated in the murder of PPP there is a strong motive for her to do so, especially if PPP had threatened to take her husband away from her. This would go against her. All the past instances of her risking her life for her husband by tripping down the stairs and slapping her childhood friend under suspicion that he was after her husband's life will now be used as evidences to the extent Prachi will go to safeguard her husband. Now if Ranvir wants to take revenge against Milsi, what better way than to get his wife locked up in prison? Milsi will suffer a thousand deaths to see his wife behind bars than if he himself is behind bars.