Detectives come in many guises, so take your pick – a middle-aged eccentric in her quiet cottage in St Twadey or the tough Lieutenant in the mean streets of Los Angeles.

There is something appealing about M.C. Beaton’s crime stories, which are set in the Cotswolds and feature Agatha, a 50-something testy, divorced detective with her tinted, glossy hair, thickening waist and arthritic knee.

In Agatha Raisin and a Spoonful of Poison (Constable £18.99), she is once more in hot pursuit of romance when she spies the dishy, green-eyed widower George Selby living alone in the “odd, secretive” village of Comfrey Magna nearby.

How to impress him? She will use her considerable powers of persuasion to help publicise the fete run by George and the vicar. But all hell is let loose when the home-made jam is found to be injected by LSD.

An old pensioner flies off the parapet of the church tower and another jumps into the river. Agatha’s enquiring instincts go into over-drive as she homes in on the vicar’s new, glamorous wife as being the guilty party. Our feisty detective brings humour and drama to English village life, making one think of Alexander McCall’s joyous Mma Ramotswe and the No.1 Ladies’ Detective Agency far away in a small town in Botswana. By contrast, Faye Kellerman’s latest thriller, A Cold Case (HarperCollins £18.99), written with her usual flair, brings together a mixture of money, marriage and obsession.

Genoa, an isolated, unhappy but brilliant teenager, has never forgotten Ben Little, her perceptive, caring teacher, who was murdered 15 years ago.

Despite a profound search, his killer has never been found.

When Genoa, who is now a software billionaire, reads about another identical execution-style homicide, she is determined to open the old case.

A music producer, Primo Ekerling, is dead and the case has disturbing “overtones of Dr Ben’s murder”. The intact bodies were both found curled up inside the trunk of an identical Mercedes, and both discovered in a public park after dark.

She offers LAPD a large endowment, the team to be headed by Lieutenant Peter Decker, whom she comes to trust as a “man of principle”. Faced with endless dead ends, he enlists his daughter Cindy, a Hollywood detective in her own right, and Rina, his bright wife.

Together, they launch into the thankless task of slowly uncovering the links between the deaths of Ben, that seemingly paragon of virtue, and Ekerling, who had been up to his eyes in the drug-infested music business.