the whole point of the module is that we are studying genre. and the problem with that, is who defines genre? Is it the composers, the public or the theorists(/analysists/critics) ??
Genre is an attempt to seperate the textual world into labels and naming these labels. but its problematic as it is not a neutral nor subjective process, it can be too broad or to narrow and there are NO DISTINCT RULES for what excludes or includes a text into a genre. Features belonging to the texts of one genre might not be limited to that genre, additionally genre goes through a biological process of mirco evolution and thus there are many subversions and texts of 'mixed genre'.
WHAT DOES THIS MEAN?
it means you have the freedom to define wat Crime Fiction genre means to you and if your text fits into your definition then you are ultimetly right and cant be contested.
thanks for listening to my rant
PS: since your Terry Pratchett novels/shows are about crime..
"Crime was always with us, he reasoned, and therefore, if you were going to have crime, it at least should be organized crime."
-------Terry Pratchett, (Guards! Guards!)
they are broadly fitting into anyones description of crime genre i would think...