Bijutsu Souko no Rapunzel

On the 4th floor of the school building, there's an art storage room.
They say it's haunted by the ghost of a female student with endlessly flowing golden hair.
The truth behind the students' whispered rumors is Amane, Shusuke's childhood friend.
Ever since losing her father, she lost her voice and has been supporting herself by continuously painting.

(Source: MangaPlus)