Whistle!
The group is told that a whistle will be blown behind the back of whoever is chosen to go into the center, and that he, because of a magic coat he has put on, has clairvoyant power and can immediately turn around and tell who did it. If he should by some mishap make an error, he may try again and he can without question guess who did it the second time.
Mr. Victim goes into the center and the magic coat is put across his shoulders. Great care must be used however so that he cannot possibly see that the whistle, which is a very light one, is hanging on a short cord pinned securely on the back of the coat just between the shoulders. The sleeves are tied in front and the coat is bunched across his back so that plenty of thickness is arranged for in order that he may not feel the whistle as he turns around rapidly. Other guests crowd in on him very closely so that the whistle can be reached easily and can be blown by any one of the onlookers without the victim’s feeling the tug.
When the leader says that all is ready, someone back of him blows an earsplitting blast on the whistle. Immediately everyone puts his hands behind him. Mr. Victim turns around at once and accuses the guiltiest looking one of holding the whistle. The guilty looking party holds up his hands and shows that he has no whistle and vows that he did not pass it to anyone else. Only one guess as to who did it is allowed in each case and the one accused is to hold up his hands at once, to prove his innocence or guilt.
Sooner or later the unfortunate in the center discovers who has been holding the whistle all the time, and that is the strategic time for everyone to go into the other room!