So anyway, my wife and the kids were out back, the kids were swimming in the very cold, just opened pool. I was sitting in the house watching something on the tube. Then I heard the screen door open and Troup (the nearly a year old mastiff pup) let me know about it. He gave out a couple of very loud barks. This was followed by footsteps running away from the front of the house.
I went and took a look outside, but didn't see anyone. Though the screen door was left open.
My guess is that he scared off a potential burgler. What a good boy he is :-) .