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FORT WALTON BEACH (CBSMiami/AP) — A 15-year-old from Fort Walton Beach, accused of shooting his older brother, is facing murder charges, authorities said.

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Okaloosa County Sheriff’s officials said the brothers were fighting Tuesday when the suspect grabbed a gun from his room and shot his 19-year-old brother, Anthony Nix. The boys’ mother said she tried to intervene and as Nix ran from the house, her younger son followed and continued shooting.

It’s unclear what prompted the argument. Authorities said the suspect went after his brother with a butcher knife prior to the shooting.

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Nix was taken to the hospital. His condition was not released.

The suspect is not being identified because he is a minor.

Authorities said the suspect admitted to the shooting. He is also charged with aggravated assault with a deadly weapon.

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