"Even if that is the case, wouldn't it still show how much you were thinking about this matter? After seeing as how repentful you are, and how much you are helping with the investigation, I am sure that your grandfather would not be too overly harsh on you. Besides, all you have to do is keep insisting that Qin Hu is suspicious.
With your grandfather's current mood, he will certainly do everything it takes to make sure of the truth of this matter. When that happens, it doesn't matter if Qin Hu had done it or not. It will not be important, as you will be able to improve the reputation of the Tang Family by removing the pests for the common people, so why not do it?
Continue to reel him in…