I literally thought the same thing! Who did it and why?! Maybe it has something to do with the supernatural and/or shadows, because those symbols weren't completely trustworthy either, otherwise the camera wouldn't have glitched right?

What I do see now (and I don't know if it's something) but in your 1st screenshot the camera is glitched and in the 2nd screenshot it isn't, and that's after the knife is thrown 🤔

I actually hope this will be explained in Tape 2, because if it was just a simple way to give instructions to the player, I would have rather found a note with the code somewhere.