A locked door thriller for April: The Secret Room by Jane Casey, The Other People by C. B. Everett, This Is Not A Game by Kelly Mullen

The beautiful second wife of a successful businessman walks into a five-star London hotel for a weekly tryst with her lover, but within an hour she is dead.

The lover finds her submerged in a bath of scalding hot water – but she did not drown. So begins this magnificently serpentine mystery investigated by determined but spiky DS Maeve Kerrigan and boss DI Josh Derwent.

But before the pair make much progress Derwent is arrested on suspicion of brutally abusing his female partner when he is discovered standing over her inert body, covered in her blood.

A tour de force – an old-fashioned locked room mystery wrapped in a deeply moving love story.

Ten complete strangers find themselves transported to a dark and threatening mansion, where each one wakes up not knowing how they got there – or why.

When they meet in the grand dining room for dinner, they realise they are prisoners.

Then the mysterious Amanda appears to tell them the only way they can escape is to find a young woman called Claire who will die in 24 hours if they fail to rescue her. But slowly, one by one, the guests are brutally killed.

The parallels with Dame Agatha’s famous story And Then There Were None are clear enough, but this has many an extra modern twist – with lashings of horror and menace. Ingenious and constructed like an elaborate garden maze, it is a little masterpiece of suspense.

Gibson Martini-loving grandmother Mimi MacLaine, age 77, is the heroine of this much anticipated debut from an American film producer and marketing executive.

Mimi and granddaughter Addie – a video mystery game designer – are invited to a charity auction at an isolated house on Mackinac Island on Lake Huron, Michigan.

A snow storm blows in, isolating the guests, and the hostess is found dead on her bed. Then her lover, who happens to be her son-in-law, is also murdered.

Mimi and Addie take it upon themselves to become detectives. Mimi should be Miss Marple on acid – but somehow never quite is. Her dialogue just isn’t brittle enough. Instead she ends up like a pale tribute to Daniel Craig in 2019 movie Knives Out.