I have had this story in my head for the past few days, but for the life of my I can’t seem to identify it!
The setting is a gentleman’s dinner club, which requires its members to wear green jackets due to an unfortunate incident some years earlier. A thief had made off with all their precious silverware, bit by bit, by posing as a guest and a waiter simultaneously. The ruse was only discovered when a detective was installed in the building, who deduced from the different treads of the thief that he was playing two characters - loud and brash as a guest, and tentative and quiet as a waiter.
I was sure that this was a Sherlock Holmes story (the distinct way in which I remember the story being told in the past tense would lend itself to that), but I have read damn near all the wikipedia synopses of Conan Doyle’s short stories and it doesn’t seem to be among them.
Help me out, dopers!