A Last Lonely Breath by Keith Nixon is book 9 in the Solomon Gray series, and, in my opinion, it's as good a series at book 9 as it was at book 1. In book 1, Dig Two Graves, we were learning who Solomon was and what made him tick and through the series that's developed. Like a lot of fictional detectives, real life ones too in fact, Gray has his issues, I hate spoilers in reviews so I'll not be detailing them, but he struggles on, doing the best job he can, always giving the best of himself.
There's a dead ex council leader, a dead body at the side of a remote road and vapes are killing people, plenty of cases going on but Gray is acting DCI and meant to supervise, and he hates being stuck behind a desk, so instead he's out there in the thick of it.
Keith Nixon writes great books, I've read a lot of crime fiction and he's definitely one of my top authors, and Gray one of my top characters. If you've not read them then give yourself a treat and get started, you'll not regret it.