One can only speculate, but I'm sure it was something bad, you see, evil or simply "deadly" happenings open the door to supernatural entities, ghosts, demons, poltergheists, you name it, this is why in multigenerational homes "grandad's ghost" is still looking for his glasses, why in morgues and hospitals there are "shadow men" everywhere, and why murder crime scenes are haunted.
Death calls these things, and this guy most likely called something, even if he didn't go through with it.