Actually this is a slightly different version of the Twistery that went up on twitter. Someone got that straight away, so I thought I’d better make it a bit more devious:
There was sawdust around the body. The only footprints belonged to the dead man. Who stabbed him and how did they get away?
(I’ve gone back to the wording of version 2! Indecisive, me? Uhm, I think I might be, I’m not sure. Anyhow, the full solution is coming soon…)