Me either, I'm trying to have a relatively pressure-free year of reading, so no challenges for me this year. I hope you enjoy your Round Robin challenge !
I'm not entirely sure myself what the difference is between thrillers, mysteries and detective novels! But a lot of those Dutch ones say 'literary thriller' on the cover, so that's how I know about those. For others I try to see what other people on GoodReads say or what the synopsis says. Generally if it's a police investigator / detective working on a case, I call it a 'detective' (or mystery) and if it's someone not related to or experienced in policework but just a civilian being threated and chased or looking into the case, then I call it a 'thriller'. Generally for me in a detective it's more about solving the case but in a thriller it's also about the main character trying to avoid being killed themselves, if that makes sense? But what I do is probably not how other people would do it, I just do my own thing in my own bookshelves and collection (I have separate shelves for detectives and for thrillers). Indeed murder and mayhem .
Ohh I bought that Christmas one at a library sale, it has terrible reviews/ratings on GoodReads, one of them might have been yours . I haven't read it yet, but I have read a few of his thrillers and enjoyed those when I was a teenager. I was a young teenager with my family on holiday in France (with our big tent), I had read all my own books so I decided to have a look at my parents' books (while I was inside the tent looking for something to do), and there I found De Cliënt by John Grisham (or The Client as the English original is known). The story spoke to me at the time because one of the characters in the book was a child, so I felt like I could relate a bit. I liked Patricia Cornwell when I was a younger teenager but I haven't read any of her books since, so I don't know if they would still appeal to me.