I only picked this one up because I'd missed the last two episodes on TV and was very disappointed. What worked well as a TV show, with regular cliff-hangers, was annoying in print.
It's not a short book but the constant rise and fall of suspects in and out of er.... suspicion, quickly because formulaic since one always knew that the right person had not been nabbed for the crime because it wasn't anywhere near the end yet.
So, great TV show, not so great book. One for the charity bookshop I fear