Man moves into apartment and finds a lot of fascinating but disturbing art

[Samara]

The story follows a character (I'm pretty sure it's a man) who moves into an apartment or home and finds a lot of incredibly intricate and fascinating, but disturbing art. If I remember correctly, the art is mostly drawings and there are stacks and stacks of them and the description either compares them vaguely to "The Garden of Earthly Delights" or I thought the description reminded me of that piece—but that's the vibe of the art found. The main character becomes obsessed with the drawings and tries to find out more about the person who lived there before him but has trouble finding much except that I think it was an old man and that he just disappeared or something. I think the main character ends up releasing some of the less disturbing art as his own at one point and it becomes very popular but then someone comes forward having recognized the art or something? I am desperate to find this book so I welcome any and all ideas!!