Dead Water, By Ann Cleeves. Macmillan, £16.99

Crime fiction has a demanding convention. If the serial killer arrived recently on our gory shelves, the serial detective has been around for so long that readers expect it, and look forward to the regular appearance of their favourite sleuth. This lands the writer in a dilemma: how to maintain a character while bringing a book reasonably up-to-date? Ann Cleeves presents another adventure for her somewhat exotic Shetland detective, Inspector Jimmy Perez, but has taken a bold step with a dramatic change in his life.

Jimmy, he of the flashing eyes, was introduced to us via Fran Hunter, heroine of Cleeves's first Shetland book. Jimmy and Fran soon got together, but now Fran has been killed and we start Dead Water with the grief-stricken Jimmy having difficulty in functioning.

New investigative blood must be brought in when a body is discovered in a boat. Inspector Willow Reeves is also from the isles – but a different group, the Hebrides .

Willow is a lot less pliable than her name suggests. With the intermittent aid of Jimmy, she sets about confronting a spiky and powerful islander, for the owner of the boat is no less than the Procurator Fiscal (public prosecutor) herself. The identity of the victim generates numerous suspects, for the deceased is a reporter connected with some juicy scandals – not least the pregnant girlfriend he left behind to make his career.

If the sad figure of Jimmy Perez has moved on from the confident crimebuster of earlier books, Shetland itself is changing. Cleeves records this with a sharp though sympathetic eye. The oil boom is over and some locals are looking for new ways of investing their money. Renewable energy is attractive, and the Shetlanders have become sophisticated dealers in the business world.

The dead man was involved in a syndicate for producing tidal energy, a community venture in which Willow gets the whiff of malpractice. And one of the major investors was the Procurator Fiscal. All this intrigue makes for a solidly constructed piece of crime fiction, with the grieving detective as a touching and original figure at the centre.