Here is the story:
On 23 March 1994, the medical examiner viewed the body of Ronald Opus and concluded that he died from a shotgun wound to the head. The decedent had jumped from the top of a ten-story building intending to commit suicide (he left a note indicating his despondency). As he fell past the ninth floor, his life was interrupted by a shotgun blast through a window, which killed him instantly. Neither the shooter nor the decedent was aware that a safety net had been erected at the eighth floor level to protect some window washers and that Opus would not have been able to complete his suicide anyway because of this.
Ordinarily, Dr. Mills continued, a person who sets out to commit suicide ultimately succeeds, even though the mechanism might not be what he intended. That Opus was shot on the way to certain death nine stories below probably would not have changed his mode of death from suicide to homicide. But the fact that his suicidal intent would not have been successful caused the medical examiner to feel that he had a homicide on his hands. The room on the ninth floor whence the shotgun blast emanated was occupied by and elderly man and his wife. They were arguing and he was threatening her with the shotgun. He was so upset that, when he pulled the trigger, he completely missed his wife and pellets went through the window striking Opus. When one intends to kill subject A but kills subject B in the attempt, one is guilty of the murder of subject B.
When confronted with this charge, the old man and his wife were both adamant that neither knew that the shotgun was loaded. The old man said it was his long standing habit to threaten his wife with the unloaded shotgun. He had no intention to murder her -- therefore, the killing of Opus appeared to be an accident. That is, the gun had been accidentally loaded.
The medical examiner closed the case as a suicide.