This is all hypothetical since no one on this thread actually owns a firearm. That being the case then my answer would be a 9mm loaded with federal hst. I would say a quick prayer as I am grabbing a flashlight and the 9mm and then proceed to investigate in order to identify the target. I would then confront the target and tell him about Jesus and ask if he knows Him. If he says yes then hopefully the Holy Spirit will convict him and he leaves. If he says no but he wants too and repents and believes in Jesus then my decision is to either go ahead and send him on his way to meet Him or not. However if he does just want a bacon sandwich then who could blame him?