my mom was pregnant with my brother. her body was attempting to go into labor too early, so she was ordered to bed rest. we had various family members in and out, to check up with, and visit her during that time. my aunt was over quite a bit. we lived in the swamp, in the basic middle of nowhere, so durng the day, the house was never locked or anything, and back where we lived, we had no accidental visitors. it was hard to find even if you WERE looking for it.
i was laying in the living room floor, watching TV. i knew my aunt was coming over to visit my mom later, but she'd let herself in, no worries. at some point i heard keys in the room behind me, but watching whatever-it-was, couldnt be bothered to turn around.
a voice (female) said "is your mother asleep" and i replied "no, just laying down" "ok" the voice said.
i didn't think anything of it. during the next commercial break, i went in my mother's room, and was alarmed to find her all alone. i asked where my aunt had gone, and my mom told me she hadn't shown up yet.
no one had been to our house all day.
over the years, we had quite a few instances of this. the sound of keys, followed by a distinct "hello?" or other question.