SPOILER WARING! DO NOT READ ON IF YOU DON'T WANT SPOILERS!
I solved it! I suspected the butcher was involved, but it didn't make sense to me that he would be the killer. I had to do a lot of brainstorming to determine that it had to have been the prisoner that did it. Ultimately what helped me eliminate the other candidates was their love of the town.
Even though the old man hated tourists, hate is not a crime. He even vouched for the people of his town, saying they were good people. A killer wouldn't do that, I think.
The drummer just wanted to drum, even if the old man didn't appreciate him. He wouldn't have any motive beyond enjoying his art.
The smoker tattled on the butcher because he cared about the people the butcher had exploited. No reason to think he'd have motive against anyone but the butcher (who incidentally is still alive).
The tourists just wanted to enjoy their time there. Even the old tourist, who didn't have much to say, still likely would have fled if he had been the murderer. Why stay at a tourist destination if you could become a suspect?
I determined that the butcher had to be involved with the prisoner, but I wasn't sure if the butcher was connected with the murder, since he was willing (at length) to give us a lead (his scapegoat) on the prisoner.
The prisoner didn't outright deny that he had been the killer; just posed the quesiton "How could I be the murderer?" He covered for the butcher, saying that the butcher couldn't have done it, and gave no further information.
Following all of the clues shared by the witnesses, I knew that something had happened at the prison, so I concluded that it had to have been the prisoner; I just didn't know how. It makes sense that the butcher would have used him to eliminate a rival.
Thanks for a fun teaser!