Ask for the name of a western novel

A bunch of strangers receive a mysterious letter and are invited to an island (possibly for a vacation?). There was only one ship that traveled between the island and the mainland, transporting daily necessities. It traveled back and forth about once a month. The people on the island were murdered one after another. People were suspicious of each other, but in the end, everyone died. The last fisherman who picked up the drifting bottle understood the whole process. The one who planned the whole thing was a judge. All the people who were invited were guilty, but they all escaped the punishment of the law. Therefore, the judge planned the action to make these people receive the retribution they deserved. What left a deep impression was that the judge first created the illusion that he was killed (he was also on the island), then hid and killed others, and finally committed suicide.
There was a ballad on the piano in the room. It was about seven brothers going out to wander. Some were crushed to death by rocks, some were hanged, and so on. They died the same way as everyone else.

Answer 1

I can't answer this question because I don't know which novel you're referring to. If you can provide more context or specify the type of work you are referring to, I will try my best to provide you with a more accurate answer.