Detective Puzzle

C is the killer and C killed B.

Let us examine all the hints that are given,

• From deduction no.9. We can say E is cleared as the killer is E’s brother
• From deduction no.1. We can clear A, as A recently ran in a marathon, and the killer had leg surgery. Therefore we can assume that he is in no state to run a marathon.
• From deductions no. 9 and 5. We know that D met E six months ago, while the killer and E grew up together in Seattle. Therefore D is not the killer.
• From deduction no.8. C had plans with D for the upcoming week, so we can assume that C is alive.
• From deduction no.2. Since B moved into the city and wanted to be a farmer, we can assume that he did not grow up in Seattle. Thus B is not E’s brother.

Since we have cleared everyone except B and C, we have deduced that C is alive, while not having any information about B’s whereabouts. We can conclude that B is dead and C is the one who killed him.