My family believes that either somebody keeps breaking into our house or it is haunted

Scene one: A few months ago, my wife and neice came home at night to an empty house (I was playing poker–hey, it was Saturday night). Once inside, with the dogs and cat downstairs with them, they heard footsteps and a door close upstairs. They rushed outside, and sat in the car. Their futile attempts to pry me away from the card game convinced them to call my friend who came over with his handy .357 to sweep the house. Even he thought he heard something when he got there. My wife swears that she saw a black light flash in our bedroom window (our wireless internet connection could account for that). Spooked friend sweeps house, finds no evidence of intruder or of a way to enter house. I laughed at them and said they are all weenies.

Scene Two: Yesterday, in the afternoon, my 18 year old daughter was home alone. Suddenly she was standing at the top of our stairs and noticed that the light above her was on. Dogs and cat were accounted for. She didn’t turn it on, so she got a little spooked. Suddenly a clothes basket fell off the washer 6 feet from her. She scurries into my room and locks the door and calls me at work. For my little girl, I came home in 10 minutes. While I was en route she heard what she thought was a door close. I turned on our street and saw a stranger’s car with a guy sitting in it, but that was 2 blocks from our home. I get home and sweep the place with my .357. I must admit it makes the hair  on the back of my head stand up going into rooms and peering under beds and in closets when you think a bad guy might be waiting to jump you. Nobody found, all doors were locked and bolted from inside, but back window was unlatched and could have been means of egress and ingress. Later we learn of what transpired in Scene Three to our niece, who didn’t want to mention it.

Scene Three: Last Saturday niece was home alone during afternoon. She was upstairs when she heard kitchen cabinets open/close, and dishes in dishwasher rattle. She assumed we were back home, but looked out and saw no car. She went into bathroom and locked door until we returned, then felt too foolish to tell us. 

One weird thing. A while back, I came home with wife and noticed a house key sticking up from behind our front light beside door, sorta half in and half out. Nobody who might have ever  had a key to our front door either remembers or admits to putting it there. We live in a neighborhood surrounded on all sides too close for comfort by other neighbors.  No evidence that anybody has ever taken anything or disturbed anything. No complaints from anyone else in neighborhood of unlawful entries. WTF is going on?

Now, none of my ladies want to stay home alone.  That’s the real problem. Is this all a plot to get me to give up playing poker into the wee hours of the night? Is our house haunted? Have we heard an unwanted visitor three times so far, but never seen him/her? Or are the girls just spooked and their is a logical explanation for each incident? Halp. I need explanations. Call me cornfused in Glen Allen.