I enjoyed this. It was goofy and over the top, but really fun. Professor Bill Yates is the sort of person who would drive you crazy in real life but is entertaining to read about. He is irrational and absent minded. He forgets what happened two minutes ago, he mistakes what he thinks for what happened and imagines the most lurid explanations for things and then forgets they aren't true. At one point he thinks to himself that if he and Brian could sit down and consider the events carefully for a few minutes they could figure them out. And this is funny, because that's never going to happen.
Bill and Brian are a good pair because they are both crazy enough for anything. They take turns taking stupid chances. I have a distaste for TSTL (too stupid to live) detectives in mysteries, but these guys aren't detectives, and TSTL is in their DNA. I was rooting form them to get together because they were such a match and besides, no one else deserved their wackiness.
The mystery was of a piece with this mood. Each character was more suspicious than the last, and the MC's were no help at all in eliminating anyone. Nor was the sole semi-competent cop, since he was fixated on the solution he wanted and the MC's were hiding all the evidence from him. I did suspect the eventual solution, but since I also suspected about five other people, that isn't saying much.