Do [spoilers] leave a corpse when they die?
Inhabitants will not create a corpse.


The term "corpse" is mentioned one time in the rulebook (not counting an example haunt), in the Dying section. This refers specifically to one of your traits moving to the skull, which kills the character and creates a corpse.


  DYING
  
  Once the haunt begins, if any of your traits moves to the skull, then
  you die. Tip over your figure on your tile. DROP all your Items,
  Omens, and Objects. You are now a corpse.
  
  Even if the traitor dies, as long as the monsters can complete the
  haunt’s goals, the monsters still get their turn (under the traitor’s
  control) and the traitor can still win.


From the Rulebook PDF


   Your traits refers to the traits of a player's character.