Peter Lovesey’s new mystery, “Diamond Dust,” is a keeper.

It has tension, emotion and a smorgasbord of red herrings.

It is Lovesey’s seventh novel about Inspector Peter Diamond, head of the Bath, England, murder squad.

As the frequently poignant book begins, a case ends with a conviction. The next morning, Diamond goes to a new murder scene in a city park. He lifts the sheet from the corpse. “His skin prickled and his muscles went rigid as if volts were passing through them.” The victim is his wife.

Diamond, of course, is told he can’t be in charge of this investigation. He’s involved too personally.

So, although he’s a police inspector, he has the amateur detective’s problem of not having access to police labs and information. He grieves greatly and is questioned as a suspect, which makes him furious.

There are plenty of suspects in Diamond’s mind from somebody he’d put away to a hit man hired by that somebody and to his wife’s ex-husband.

Then another police officer’s wife disappears. She is found shot to death, like Diamond’s wife. However, unlike Diamond’s wife, the second body had been hidden.

Diamond teams up with the other widowed officer who also isn’t supposed to be working on his wife’s murder following more trails of old cases they’d both worked on, and meeting more dead ends. Friends warn Diamond to be careful: “There’s a professional gunman out there. You may think you’re on his tail, but he’s on yours.”