Authorities in Mississippi say a 9-year-old boy has shot his 13-year-old sister in the head and wounded her after an argument over a video game controller.

Monroe County Sheriff Cecil Cantrell told local news outlets that the girl wouldn’t give up the video game controller when her brother wanted it on Saturday. He says the boy shot the girl in the back of the head and that the bullet entered her brain.

The girl was rushed to Le Bonheur’s Children’s Hospital in Memphis, Tennessee. Details of her condition weren’t immediately known Sunday afternoon.

Authorities say they don’t yet know how the firearm used in the shooting had been accessed. The sheriff added that the circumstances of the shooting are still being investigated.

Monroe County is in northeast Mississippi.