assault rifle injury type pattern which rips and spreads apart organs in your body, tissues in the body, vessels as they are going through. our tactics are changing for law enforcement. we go side way, now to the front to expose less organ injuries. >> that's interesting. instead of going like this. >> go side way and goes through both lung and the heart and the other side where you go from the front now you have a plate that protects your heart and one lung or the other you can still be functional. >> that's fascinating. because you see people approaching the lower profile. >> reporter: he grew up in iran and served in the military there so guns and combat aren't new to him but he never thought he'd have to use those skills in america. did you ever think your experiences in the middle east were going to be useful here? >> never in a million years but now that i am here, i am, you know, this is one of my duties. i mean, when you sign -- it's a