Janet Neel Death's Bright Angel (1988)
This is a book which I have re-read a couple of times over the years since it is really a cut above the general crime thriller - the writing is excellent, the large cast of interesting characters is handled deftly, the romantic bits are not over the top and it has a tasty plot. I have read a couple of the sequels (A Timely Death; Death Among the Dons), but they don't pack the punch of no.1 in the Francesca Wilson/John McLeish series.
The brutal murder of a business-man in London leads Detective Inspector McLeish and his charming side-kick Det. Sgt. Davidson to a Yorkshire textile manufacturer in financial difficulties (a completely believable 1980s scenario indeed). Coincidentally, Francesca Wilson is part of government team advising Britex Fabrics but she also has family problems which bring the Inspector into her life in London...
The heroine is ultra-intelligent, striking-looking (not beautiful, but her legs are excellent!) and reluctant to give up her hard-won independence. Francesca has almost single-handedly brought up four brothers. The family quirk lies in their astonishing musical ability: all are prodigiously talented and one is a cross-over pop-star tenor. They add a lot of background interest to the book, as does the recurring musical theme (oh, pun) of wonderful music (the Messiah; lots of Bach) and the gorgeous The Lost Chord (from whence 'Death's Bright Angel'). A very good time-waster.
BTW, I like the neoclassical-inspired cover of my copy better than the current ones:
If you liked this...: coppers with memorable side-kicks who fall for independent women they encounter in the course of their work - I think probably Ngaio Marsh's Inspector Alleyn is the way to go.