The buzz of an all-terrain vehicle may have triggered a deadly shootout that led police to file a rare charge of "murder by duel".
Simpson is accused of killing Dana Martin, 39, in an April 20 shootout a few hundred yards (meters) from Simpson's home.
"We've had shootout-type cases, but I can't recall one quite like this where there was an argument, then the people separated and came back to the very same location, each knowing the other had a gun," said prosecutor Sid Bell.
The law, written in 1849, reads: "If any person fight a duel in this state and in so doing inflict a mortal wound, he shall be deemed guilty of murder." West Virginia became a state in 1863.
The felony carries the same penalty as first-degree murder, up to a life sentence, McCarty said.
Witnesses saw the men argue in the road, part ways to retrieve handguns and return with weapons, Bell said. Testing determined that both weapons were fired. Martin was fatally shot in the torso.
Witnesses told police that Simpson was disturbed by the roaring sound of an ATV that Martin repeatedly drove past Simpson's house while helping a woman move.
A call to Simpson's attorney, Lacy Wright Jr., was not immediately returned.