In the beginning they of course tried to deny everything. But one of the assessors, who once had been a servant to Anno, knew what a wrathful master the archbishop could be and decided he better tell the truth. He was allowed to keep one eye so that he could lead the others back home. Gruesome stone masks with eyes that looked like dead were put above the entrances to the houses of the thirteen in order to remind the citizens of Cologne of what would happen to people who did not abide by the law in this city. T hus the legend.
Reality is much more harmless.
The head does not have a lower jaw. But it does have very impressive metal teeth, which at their points almost touch each other like a V. Behind them there is a hole in the wall. In former times they used to put a rail between the teeth, which was then safely held inside the hole. Across the rail they hung a rope which could be used as a very simple sort of pulley to get things out of the cellar or lower goods into it. The mask is simply there for decorative reasons.