Mystery:1

You are a detective.you went to a house and saw a old man dead on his chair.he had a heart attack.you wanted to see the water he drinks.but you dont see the well.you ask the Neighbor he barely knows the guy. You go to all the houses but they dont answer. Then you pull out the record and see that the first neighbor is the owner of all of the houses. So you look for yourself. You found it and it had cynide which leads to slow heart attack. It had a footprint of a show which is 11 and the old mans shoes are 9. You walk to the first neighbor and notice the buddy shoes and the door opens.what will you do??