I have only fairly recently encountered the wonderful Peter Diamond detective series, so forgive me if I’m late to this particular appreciation society.
Diamond Dust, published in 2002, is the best and the most moving of Mr. Lovesey’s books that I’ve read so far.
This book, the 7th in the series, is an emotional read and one that I literally couldn’t put down.

For obvious reasons, I can’t & won’t plot-spoil, but trust me when I say that this is a gripping whodunit like no other.
There are twists and turns in the plot that had me fooled right until the end. There is emotion a-plenty, and the writer carries the reader along in a masterly mix of drama, murder, and raw human emotion.
That’s about all I can say without spoiling your enjoyment of this murder mystery.
Personally recommended.