This happened a couple of years ago... to this day I'm not even sure what it was or even if it was something paranormal to begin with. From the best of my recollection, it took place one after 11PM. I was sitting in the room where I have my consoles setup and playing some XBox, while my wife was in the adjacent room. We both heard a loud bang that seemed to be coming from our basement. I went into the room where my wife was and we both inquired from each other if we were the ones who made that noise. Then we heard it again and got scared, like someone banging on the wall downstairs and really loud too. At that point, we got scared and thought that someone had entered our house and I began to doubt whether I had locked the garage or not. So we barricaded ourselves in a room (or rather just locked the door) and called 911 saying that it sounds like someone had entered our house and we heard banging sounds from the basement. After asking us questions to make sure that it couldn't be a child or pet who might be downstairs, they sent some cops over. While waiting, we also heard what sounded like footsteps in the basement. Anyhow, shortly after, the cops arrived, we let them in and then they had a look downstairs as well as around the house outside. There were no footprints seen outside (which would have appeared in the snow. There was around 3-4 inches around that time). And they found...absolutely nothing. No signs of forced entry and all doors and windows were closed and locked. And of course, they didn't find anyone in the basement either. Well, I did confirm that I had indeed locked the garage door. We haven't heard anything like that since. Though it doesn't particularly bother me, every now and then I wonder what it could have been. Thoughts?