Authorities say 69-year-old Tom Wilson was justified in shooting 21-year-old Dallas Two Bulls, saying his life was clearly in danger.
The state's attorney's office has released images of Wilson's injuries.
In the early morning hours of September 25, police responded to a report of a shooting at a residence in North Rapid. They found Two Bulls dead from gunshot wounds and the homeowner, Wilson, severely beaten.
"The evidence indicates that this was self defense," Pennington County State's Attorney Glenn Brenner said.
Brenner says that Wilson was in the home with Two Bulls' twin sister, and that she called Two Bulls for a ride. But that's not what happened when he showed up.
"When he broke into his home he removed a bat from Mr. Wilson's hands, the shooter's hands, and began to beat him with it," Brenner said.
Images released Wednesday show the severity of the injuries that Wilson sustained before firing the shots that ended Two Bulls' life. It's one of the factors investigators used to determine the shooting a justifiable homicide.
"We use a reasonable persons standard to determine whether or not a reasonable person in the same set of circumstances would think that their life was in jeopardy and that they were threatened. And in this particular case that's exactly what we had here," Brenner said.
Wilson, Two Bulls and the female witness were all intoxicated at the time of the shooting.
"It was a senseless event that took the life of another. However, under the law the appropriate decision has been made, which is not to formulate any charges at this time," Brenner said.
Investigators did find some of Wilson's property on Two Bulls body after the shooting. They say it indicates that robbery may have been Two Bulls motive for the break in and assault that lead to his death.