I'm a librarian who loves anime, manga, and reading a wide variety of genres.
On Saturday someone noticed that one of the windows at work was completely broken. It was an indoor window and would have had to have been broken by someone in the building. From the look of things, it was either done by someone tall or someone who had swung something over their head onto the window. No one noticed during closing procedures on Friday that the window was broken, so either it was broken and somehow no one noticed (it's shatter-proof glass, so it's all still in the frame - when I first saw it I thought the window was covered in foil), or someone was in the building after-hours and broke it. Or at least that was the theory.
We happen to have a security camera pointed in that direction, so a few staff members and campus police took a look at the footage. A little after midnight, well after closing, the window spontaneously shattered.
We used to have a display case that, due to vibrations from the doors at the building's entrance (or something - this is how it was explained to me), had spontaneously shattered a couple times over the years. Maybe this is something similar. It still feels a bit spooky, though.