I found a door in my basement that I'd never noticed before.
I'd lived in the house for three years. The basement was unfinished — concrete floor, exposed joists, a water heater, a furnace. I knew every part of it. I was down there to check on a leak when I noticed the door behind the furnace. It was set into the foundation wall, painted the same grey as the wall, and I had simply never noticed it because the furnace blocked most of it from sight.
It wasn't locked. The handle turned. The door opened into a crawlspace running under the addition at the back of the house — low-ceilinged, dirt-floored, about three meters wide and four meters deep.
In the crawlspace: a mattress with bedding. Several empty water bottles and food wrappers, some of which were not old. A battery-powered lantern with functional batteries. A change of clothing — men's, medium. And a notebook.
I didn't touch anything. I took photographs with my phone and called the police.
The police investigation found that the space had been occupied. The food wrappers were from brands currently in production. The mattress was recent — less than a year old. The lantern batteries were fresh.
Someone had been living in my basement crawlspace. Someone who had a door into the space that I didn't know about. Someone who had been there, in the dark and the dirt, in the space under my addition, while I lived in the house above.
For how long, the investigation couldn't determine.
The notebook was taken into evidence. The detective assigned to the case later told me, off the record, that the notebook contained daily entries. Very routine entries — times I left the house, times I returned, what lights were on in which rooms, what my schedule appeared to be. Written with the calm methodology of someone who had been doing it for a long time and found the routine comfortable.
The last entry was from the night before I found the door.
Nobody was charged. The person was never identified. They were simply gone.
I've since moved. My new apartment is on the fourth floor. There are no crawlspaces.
I still check behind every large appliance.