Somebody's knocking on the front door at 4 AM on 6/26/2014

Interesting. There was a knock at the front door. Zoey heard it too. She started barking. Since I was already in the living room only took me a few seconds to get to the door and open it. I grabbed the gun first. Imagine that. There was no one there. Zoey took off outside and could not find anyone. Wonder if it was Jeff?