I feel like either this can’t be real or you embellished how sure you are of what you heard. If this really happened, the only reasonable response would be to put a knife under your pillow, install a night-vision security camera, and then spend the next few nights pretending to sleep because there’s no way you’re getting any real sleep. You’d also involve other people if you knew anyone.

Burying your head in the sand and waiting for the guy living in your attic to kill you is definitely a BS response to what you described.