Mr Creosote

I've been employed at my current job for about a year and within that time we've received about five company wide emails from a very distraught HR team detailing bathroom vandalism incidents presumably repeated by the same individual.

They've struck several bathrooms with 2-3 months between events, the latest being a wall and ceiling painted brown using the artist's personal materials, another being a decoration of the toilet seat and another being a full cubicle redesign.

There's a lot of discussion over who it could be but no real leads. Initially it was assumed they were being done by a disgruntled employee but it's been a year and surely you'd get your petty revenge by stealing or breaking things if you weren't sick in the head.

The general view is of a mentally ill fetishist who blends in well enough to not come across as the type for it.

I've never seen it before and certainly haven't had company wide notices begging for someone to stop smearing excrement on the walls before.

Is this a relatively common thing in the workspace? Have you ever had similar in your job?