The shooting happened at the intersection of Highway 521 and Catoe Road, several miles south of Kershaw.
The Kershaw County coroner said 54-year-old Brenda Marie Coates died from a single gunshot wound. She was found in her car at the scene.
Late Monday, crime scene tape still hung on an old building on the corner. Deputies said the person of interest in the killing is the wife of the man Coates was with in the car. Officials have not released her name.
Bob Keiningham lives on Catoe Road and is familiar with both families.
"That just goes to show you never know. These are people that live in our area. Everybody sees them every day, from Kershaw here, just regular folks," he said.
Kershaw County Sheriff Jim Matthews said investigators recovered a bullet from the car and also found the gun used in the shooting. They wouldn't give any further details, and he would not say where the gun was found.
The few people who live nearby said it was disturbing to see the aftermath.
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"We heard gunshots – sounded like a firecracker going off. Happening so close to where we live is kind of nerve-wracking," said neighbor Dylan Hall.
Sheriff's investigators are waiting on three items sent to the South Carolina Law Enforcement Division for analysis – DNA, gunshot residue tests and ballistic tests – before they file any charges.
Matthews said his officers have already interviewed the person of interest. She is not in custody. They do not believe she is a flight risk.