LAKE CHARLES, La. (NewsNation Now) — Four girls are accused of stealing knives from a Walmart in Louisiana and using them in a lethal attack shown on social media from inside the store, a sheriff said.

A 13-year-old was arrested on a charge of second-degree murder and three other girls, aged 12, 13 and 14, were arrested on charges of being principals to second-degree murder, Calcasieu Parish sheriff’s spokeswoman Kayla Vincent said Monday.

A 15-year-old girl was fatally stabbed in the fight that broke out in the store Saturday, NewsNation affiliate KLFY reported. Vincent said investigators believe the argument may have started at a nearby movie theater.

The unidentified victim died of her injuries after being transported to a local hospital, detectives said.

It was the parish’s third killing in six months involving children.

Late Sunday, Calcasieu Parish Sheriff Tony Mancuso held a press briefing where he pleaded with parents to keep track of their kids whereabouts and their social media activity, stating he’s certain that some people “saw this coming” on social media and “never said a word.”

“This is not something we can police our way out of. I just don’t feel like this is a police matter. This is a parenting issue. People need to know where their kids are. They need to know what’s going on in their lives,” said Mancuso.

NewsNation affiliate KLFY and the Associated Press contributed to this article.