honestly only those who have a deep knowledge about the mechanisms used for the murders could solve these; the average reader wouldnt know about these things so how can they even hope to solve a bit of it? unlike detective conan, this doesnt really drop any hints about the murderer... but it is really hard to write a good msytery and the author did do his research, regardless of how plauisble these methods are, so it's still pretty good
Detective Xeno and the Seven Locked Murder Rooms