It is unclear how the boy obtained the gun, though Sheriff Cecil Cantrell stated that the motive behind the incident stemmed from the girl refusing to give her brother a video game controller.
The girl was allegedly shot from behind and the bullet entered her brain, as per the local police reports.
The 13-year-old was taken to Le Bonheur Children's Hospital in Memphis, where she died Sunday night.
Cantrell added he was not sure what charges might be filed in the case because of the age of the accused.
'I don't know if he knew exactly what this would do. That gun should have been locked up in a place where kids could not get access to it.
'Black Panther' clings to lead, nears an all-time record
Here in the USA , the film has raked in over $600 million, making it the seventh highest-grossing film in American history. Ross and members of the Dora Milaje, Wakandan special forces, to prevent Wakanda from being dragged into a world war.
The boy grabbed a handgun, which was kept in a nightstand next to the bed, and shot the sister in the back of the head, the sheriff said. I can't answer that.
According to the sheriff, the gun belongs to the mother's boyfriend and two other children were in the home at the time of the shooting. "I do know its a tragedy".
Meanwhile, Cantrell expressed shock about the incident, claiming that this is the first time they ever dealt with a shooting incident involving a kid. "We want to do what's right and we're going to get it right". She has since been named as Dijonae White.
Monroe County is in northeast Mississippi. He also asked for thoughts and prayers for the boy and his family.