This always happens to me, I have had 51 murderer victories and over 3000 deaths as the murder when it's a guess shot, they always get it right. But when I do it, I always end up shooting the wrong person.
Here's a strategy to new players.
If you are the sheriff and don't want to be killed, don't have your gun equipped, otherwise the murderer will walk up to you and kill you right away. Instead, have the gun away and act as an "undercover cop" and you are less likely to be killed. This was a mistake I made, and after I came up with this, my victories started to increase.