And how to find out the answer for the mill water murder scene or tell me because I think I checked all the places in the house but still can’t find the answer
After finding the necessary clue upstairs you need to some characters about it downstairs. The reply can affect what someone else says or what you ask, therefore just talking to everyone once without paying attention doesn't work. :) After having all necessary dialogs the option to solve the case by talking to the soldier near the corpse becomes available.
Should you have trouble to find the solution, you can find it in the FAQ section of the walkthrough. ;)