Bartholomew Roberts
Member
Here we’re talking of an intentional shot, clearly justifiable deadly force, where the victim was reluctant to kill if he could frighten instead.
Thumper summed it up nicely. In looking for cases for you, I found dozens of cases where the defendant said that they fired a warning shot that ended up killing the person they were trying to scare off. As you can tell by the term "defendant" and the fact that these are appellate cases, none of those ended well for the shooter.
The major difference in many of those cases is that the shooter was basically lying in an attempt to cover up murder; but there were some cases that look more similar to our case here. One example is State v. Winebarger, 617 S.E.2d 467 (W. Va. 2005):
Mr Winebarger ran several small businesses and carried a .22 derringer for protection. He loaned his car to his daughter and her husband with specific instructions not to park it in front of "Joe's Bar." Driving home with his wife, he sees the car parked at Joe's Bar and decides to take the car home with him, leaving his son-in-law to walk home.
Angry son-in-law shows up at his house drunk and becomes violent and aggressive. Mr. Winebarger fires a "warning shot" that strikes his son-in-law in the neck and kills him. His initial statement to officers was that he was trying to shoot up in the air to scare him off. At pre-trial hearing, his lawyer claimed both accident and self-defense. He was convicted of voluntary manslaughter and sentenced to ten years in prison. That conviction was upheld on appeal.
Now unlike our shooter here (hopefully); the prosecution was able to show that on several instances in the past, Mr. Winebarger had brandished a firearm and made threats. That was enough to sink him - and his claim that the shooting was accidental opened the door for the prosecution to introduce that evidence.
Finally, in many of the cases I looked at, there weren't many examples of single warning shots. In fact, most often, people fired several warning shots because quite frequently, the assailant interpreted the warning shots as an unwillingness to use deadly force and kept on coming. As a practical matter, I don't think warning shots serve their purpose if reading these cases is any indication.