Elevator Graffiti Mystery

I park my car during the day in a large multi-story garage that is next to the building with the judge's chambers. There are two options for ascending and descending the various levels of the garage: a claustrophobic concrete stairwell that screams, "assault women here!" or two rattly elevators with chipped floor tiles. Being lazy and paranoid, I take the elevator.

Some time back, I noticed that someone had scratched a swastika into the soft metal of the no smoking sign in one of the elevators. Disturbing, no? After a short time, someone else obliterated the mark with a key.

A week or so after the swastika's destruction, it reappeared. At first, I thought I had been mistaken that the original had been scratched out, but then I realized that it had simply been recarved on the sign in the second elevator. This time I took out my keys and sawed at it to mask the symbol. The next day, I noted that someone else had also chipped in to scratch it out.

I'm waiting for the mystery bigot to carve again. The garage is used almost exclusively by the employees in my building, none of whom seem like the type who would adorn elevators with graffiti, much less such nastiness. Apparently someone around is, though.