Strong, loud steps

Yesterday, I had to run my wife's store alone. Her bum leg was really putting on a show. The doctor ordered in some antibiotics. I sure hope they work. Anyway I was at the store by 10:15 am. The official hours are 11 am to 5 pm. Being so close to Christmas, I had a pretty steady stream of customers. So by closing time I was pretty much pooped. After 4 o'clock the customers went down to just a few. By 4:45 I finished up with the last one. I started turning off all but the main lights and brought into the store items we had displayed outside. I went back into the second show room to unplug a few items we were demonstrating back there. All of a sudden I heard s loud stomping, like someone with heavy boots or work shoes. The sound like it was in the front show room. I had locked the door after I brought in the outdoors merchandise so I couldn't imagine who could have gotten in. Naturely I rushed into the front show room to see who it was. There was absolutely no one. After checking out the store I went about finishing up closing chores. Before leaving the store I figured I'd better pay a trip to the jon which is located in the rear of the back showroom. While I was in there I again heard the sound of heavy shoes or boots stomping across a wooden floor. Only the front showroom has a wooden floor the rest are concrete. I hurriedly exited the lav and went to the front showroom. The steps sounded like they were coming directly toward me up the middle isle. As soon as I stepped into the front salesroom the steps stopped and there was no one to be seen. No way anyone could have side stepped me or hidden. These phantom foot steps appear to be harmless, but they can really be a bother. You always wonder, in the back of your mind, is there someone here, playing tricks or worse? Our store sits alone on a large parking lot. Go out the main door and look for a city block in all directions. It just does not make sense.