In ancient Persia (yes it’s Iran now) the Order of Assassins were a group who used the covert assassination of those they considered enemies of their state. This is in fact the origin of the word “assassin” in our lexicon.
There is an old and apocryphal story that one of their tactics was to enter the bedroom of an enemy as he slept, and leave a large knife stuck in the floor.
This was a signal to the enemy that his guards and walls couldn’t protect him, that they could take him at any time.
Sort of like leaving a horse’s ( or camel’s?) head in his bed. Ha!
Same message that is sent when you walk into your house/apartment and all the furniture is re-arranged.