He's known as “The Tailor”.
At least that's what Sherlock calls him. The man kills people with pins. The kinds of pins that tailors use on their suits. It's all straight forward and clean. The body Sherlock and himself see is of a middle aged man, nude and just horribly dead. Lines and lines of pins adorn him, up and down his body, like you can see the shape of the invisible coat he's supposed to be wearing, only the cloth has disappeared. John can even see the contour of the pockets and yes, that must be the seam that runs down the thigh, straight and heavy, hip to knee.
The body looks like a doll, really, outlined in black marker, small, round dots but when Sherlock leans down over the body and pulls one of the pins out, John nearly chokes. The pins are nearly seven centimeters long and John's never seen something so small look so sinister. He watches as Sherlock inspects it, presses the needled end of it against the tip of his gloved fingers so he'll know just how sharp it is. The hole that was made in the absence of the pin is small, but somehow gaping, like Sherlock's just removed a bullet rather than a fucking needle and John is nearly sick because there are hundreds of other pins in the man's body. Nothing will be left but holes when all of them are removed.
The hairs on the back of John's neck stand up and he imagines the killer watching them, reveling in the fact that now that the body had been found all the pins will have to be removed and that's just a whole new kind of pleasure for the killer, the second half of the murder.
John is just sick. "Sherlock..."
Before he can even try to look at the body again, Sherlock has taken him by the arm and led him away from the crime scene, light-handed and guiding. "What's the matter?"
"Going to be sick, I think." And he is, against the back wall of the thrift store, where the body was found, cold, white-blue and stiff in the London winter.
I've tossed out my toy, it's all used up, but I've got others to play with.
Sherlock is strangely quiet after John is done being sick, like he can’t believe that John reacted this way. Out of dozens of cases, this is the kind of murder that was just too much for Dr. John Watson.
John takes a handful of fresh snow and wipes his mouth with it, the bitter cold of it refreshing after his violent reaction to the body.
Sherlock is hovering, observing and the worried look on his face makes John feel just a bit better, but not fully.
“Do you want to go back?”
The image of the body overtakes him again he’s dizzy with it. Sherlock steadies him with a gloved hand, his expression even more concerned than before. “No... I... I can’t handle that.”
“Please, let me...” John pleads as he leans against the closest wall he can find.
“Honestly, I’m not going to force you to stay, in fact...”
Sherlock leaves to return to the crime scene and then quickly returns, taking John by the arm and gently leads them home.