I live in a two bedroom apartment in a suburb of Portland, Oregon. One afternoon, on returning from the store with an armload of groceries, I started the usual ritual of unlocking my front door. There is a deadbolt above, and a key lock in the knob beneath it, and I keep the key, which fits both, on a lanyard around my neck. I had turned the deadbolt, and before I could remove the key and insert it in the knob beneath, the knob turned first left, then right, as it would if someone were unlocking and opening the door from the inside. Thinking that my neighbor John, who has a key, had come over to finish some work he had begun on the previous day, I expected to see him when I pushed the door open. There was no one on the other side of the door... But the atmosphere was electric and there was a strong impression that someone had just been there. I called out but received no answer.
Putting down the bags of groceries, I immediately went to the phone and dialed John's number. To my great surprise, he answered, and I asked him to come over quickly and help me search for a possible intruder. I want to make it clear at this point that the front door, near which I was standing the entire time, was the only way in or out of the apartment, as the back door to the patio and adjacent parking lot had been temporarily blocked. John arrived about a minute later, and together we searched the premises: every nook, cranny, and corner... But there was no sign of an intruder or anyone else to be found anywhere.
It is most likely only a coincidence, but I learned, several months later, that a previous tenant, an elderly lady known for her helpful nature and numerous kindnesses toward her neighbors, had passed away in the apartment about a decade before I moved in.