Question here,
If you have a CCW and are witnessing this kind of crap,
Is it within your rights to shoot the perp?
If you are a straight, male, white taxpayer...you HAVE no rights.
Get with the program!
Not unless you want to go to jail...
Probably not. Depends on whether or not shooting him is necessary to stop the assault. I don't know about Deer Park, but usually you can only use deadly force to help another if the victim is in danger of death or serious bodily injury. Also, there are several other things that need to be present before you can use deadly force, and those things vary from place to place.
Shooting him after he knocked the guy down and was leaving would probably get him charged with manslaughter at least, because by that time he was no longer attacking, he was leaving. You can't just execute the perp. Legally, anyway. I guess it depends on whether or not it winds up on video.