Read the newspaper article, then come back here.
The homeowner had ample opportunity to stop and realize that the "suspicious" person was most likely a real delivery driver. He could have deduced that by seeing the vest, the package, looking for a uniform or ID card, and seeing the van. The van, if it wasn't a painted blue/gray style van as in the photo, probably has some sort of decal or magnet saying "Amazon" on it. Also, the shooter could have checked the package to see if it was a real one or not or asked the driver for his Amazon ID.
All of these red flags that this might not be an actual burglar were ignored. Stupidity isn't a defense. All the DA has to argue is that a reasonable person would have stopped an assessed the situation, likely coming to the conclusion that the person claiming to be a delivery driver really was.
The assumption that the driver was reaching for a weapon is not a reasonable one. Setting aside the above evidence that the person was not a burglar/thief, the driver did not engage in any hostile or dangerous act (as far as the article reports).
The driver was retreating and trying to get away. Taking the lack of any objective threatening behavior at face value, it will be highly unlikely if the defendant will be able to argue self-defense. Why? Given that a reasonable person would assume this is a real delivery driver who is running away, it would not be reasonable that he would reach for a weapon while at gunpoint. The defendant's fears were irrational and unfounded.
NRS 200.130* Bare fear insufficient to justify killing; reasonable fear required.
While a "furtive movement" defense can be made, in this situation that is going to be impossible. Police often use this defense, when they are right and wrong, but under circumstances that are a lot more ambiguous than this. Police are trained to absorb what is going on and make rapid judgements before using force. Even basic firearms defense courses teach this.
Look at the charges, which include "seven counts of discharging a weapon into an occupied structure." He missed seven times (thank goodness). Maybe those rounds hit houses instead of just the van (statute covers vehicles and buildings). The shooter was probably poorly trained and poorly practiced.
This situation occurred because the defendant failed to observe and process the evidence at hand to enable him to make correct and appropriate choices regarding his response to the situation. This rash decision making (or lack thereof) combined near fatally with his ignorance of the law on justifiable homicide.
I predict a quick plea bargain with very little to no jail time. A misdemeanor conviction won't surprise me. Stupidity isn't a crime, but often it leads to stupid actions which are criminal. While the defendant meant no real harm, he was so stupid that he could have killed someone.
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