Murder on the dance floor. Well, it had certainly been that. Mrs Stella Wright stabbed to death with a vegetable knife in the middle of an oldies’ tea dance. Any number of suspects on the dance floor at the time, and nobody had seen anything. And, with the average age being about 75, no-one had a clue who was next to whom at the time. In fact, Lestrade mused, some of them hadn’t even been sure who they’d been partnering.

It had therefore seemed sensible to bring in outside help. With the result the consulting git had declared he would need to use the other end of the, fortunately large, ballroom, to reconstruct the action. At which point Donovan had remembered something she urgently needed to speak to SOCO about. And John Watson managed to disappear completely.

Which was why DI Lestrade was currently being led round the ballroom by Sherlock Holmes. Anderson would be lucky if there wasn’t a second murder on the dance floor to investigate.

“Concentrate, Lestrade,” Sherlock grumbled, “this is a waltz, not a polka. Do try to keep in time. And stop hopping!”

By the time they had finished circling the ballroom for the third time, Lestrade collapsed gratefully into one of the chairs, only to look up and see a grinning Donovan recording the event on her phone.

He was about to say something when Sherlock began, “It’s all very tedious. Everyone slows as they come to the end of the room and start to come back down the other side. The positioning of the tables bring the dancers all closer together, so the murderer simply slides the knife out of the sleeve and into the victim. Everyone is concentrating on where they are going, even though one or two bump into each other – although they are generally better than Lestrade – so no-one notices until Stella Wright collapses into her partner’s arms.”

“Ignoring the slur on my dancing,” Lestrade began.

“Honest appraisal, Lestrade.”

“Do you know who did it?”

“I knew that almost as soon as I arrived. I just needed to prove to my satisfaction how it was done.”

“So, who?”

“The cousin. The one in the horribly pinkish dress. Both now widows, Stella Wright had originally married the man her cousin had been dating for months, before she stepped in. The cousin is widowed and finds a potential new partner, until Stella, now widowed herself, comes onto the scene and for a second time takes her man. She wasn’t going to let it happen again. As I said, tedious.”

With that, Sherlock called out, “Come on, John, there’s nothing more here for us.”

Lestrade looked at them as they departed. “That sod had me waltzing round the dance floor for no good reason at all. I swear one day I’ll murder him myself.”

“Oh sir,” Donovan said, “You’d better not kill the groove!”