Two men entered a Waffle House back on Jan. 21 off Chesnee Highway in Spartanburg County.
Deputies with the sheriff's office said 19-year-old Dante' Williams had a gun and told customers to get on the ground.
The robbery incident isn't a script from a movie, but it is a tough reality for Tamika McSwain.
"The truth needs to come out," she said.
Deputies said a customer shot and killed Williams, who was McSwain's cousin. Investigators said the customer told them Williams pointed the gun at him and he told Williams to stop, then shot and killed him.
Investigators didn't charge the customer based on the state's "stand your ground" law.
"They're covered under that law, that's the most ridiculous thing I've ever heard in my life," said McSwain.
The law gives people a right to protect themselves if they feel threatened.
On Friday, McSwain called what happened to her cousin "vigilante justice."
She said family members say Waffle House surveillance video shows a different story.
"He was shot here, he did not know what was coming," she said as she pointed to the back, right side of her head. "This guy got up from his seat and shot and killed him."
She said her family isn't justifying the actions of Williams that day, but she said he didn't deserve to die.
"I'm still kind of like in disbelief," said McSwain.
Investigators later arrested the other robbery suspect, Kenneth Craig, and charged him with armed robbery and possession of a weapon during the commission of a violent crime.
During a meeting several weeks ago, Spartanburg County Sheriff Chuck Wright said he wished the customer would've called 911 so deputies could handle the situation, but that didn't happen.
Family members said Wright told them he will review the video again.
Investigators said the customer who fired the shot has a concealed weapons permit.
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