So, there's a murder in this, but weirdly enough I'd say that the "mystery kittens" storyline was actually the primary one and the murder was secondary. Charlie did his best to stay out of the murder investigation as much as possible, and all of it was resolved off-page, to the point that I had a little trouble following the threads.
The kittens were cute, and that storyline was resolved in a way that was warm and fuzzy but not to a completely unbelievable degree. Although I did have trouble believing that someone who didn't initially want pets would say "sure, I'll take all five kittens." Five kittens turn into five cats, and that is a LOT to take on all at once
I just stopped to look at the book description again, because what's currently happening doesn't quite match what I recalled from the description. Whoever wrote that must have been working off an earlier draft of the book or something, because it's way off base on one key aspect. It says that Charlie's girlfriend, Helen Louise, ends up suspected of murder because several party guests overheard her having a loud argument with the victim. In reality, it was the local pharmacist's insanely jealous wife who had the loud argument, and she hasn't yet been brought up as a major suspect because her husband dragged her home well before the murder happened.
No one's been murdered yet, but we do have some mysterious kittens dropped off by someone the main character, Charlie, thinks is probably a frightened child, and a new neighbor who insists that she has a long history in the area but who no one seems to know anything about or even fully remember (one person thinks she looks somewhat familiar, but that's it). There have been several scenes of Diesel acting as the kittens' adorable babysitter, letting Charlie know when the tiny idiots were doing something that might get them hurt.