The Haunting in Colorado

p.s. by the way, this morning was the second day in a row that our kitchen/porch door was locked. I have no recollection of locking it... we usually just keep the porch/outside door locked so we never lock this particular door. So either:

1) in some kind of paranoid blur, I have been locking this door and not remembering
2) we have a ghost
3) we have an intruder (possibly the landlady??)

What's really weird is that the lock requires a key on both sides.