He could easily have had a gun hidden, so how can you be sure anyone does not have a gun? If a stranger is on your property after dark he should be walking towards your door, anything else, like trying to hide somewhere, or prowling about, you have to do something about it, especially if you have a family to protect.
No one should ever be on your property unless they are there to see someone who lives there. Anything else and they deserve all they get.